【每日逻辑练习第二季】【1-7】

UlysessHope

朋友们，实在抱歉，最近照相&体检&验血&看病号同学&考试搀和在一起了，忙得记错了额（= =| 我记得是今天 原来记错了）
大家加油哦！
点击查看跟帖做题方法
【精练】谢谢小意达de花儿啦~~~ （啊。。前几天重装电脑发现不能复制字体了只能截图，待我在研究研究，下次改成文字版 >_<）
Loggerhead turtles live and breed in distinct groups, of which some are in the Pacific Ocean and some are in the Atlantic. New evidence suggests that juvenile Pacific loggerheads that feed near the Baja Peninsula hatch in Japanese waters 10,000 kilometers away. Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from turtles at the Japanese nesting sites.
Which one of the following, if true, most seriously weakens the reasoning above?

(A) Nesting sites of loggerhead turtles have been found the Pacific coast of North America Several thousand kilometers north of the Baja peninsula.
(B) The distance between nesting sites and feeding sites of Atlantic loggerhead turtles is less than 5,000 kilometers.
(C) Loggerhead hatchlings in Japanese waters have been declining in number for the last decade while the number of nesting sites near the Baja peninsula has remained constant.
(D) Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from Atlantic loggerhead turtles.
(E) Commercial aquariums have been successfully breeding Atlantic loggerheads with Pacific loggerheads for the last five years.
【逻辑链】
25. (30261-!-item-!-188;#058&004144)
Twelve years ago and again five years ago, there were extended periods when the Darfir Republic's currency, the pundra, was weak:  its value was unusually low relative to the world's most stable currencies.  Both times a weak pundra made Darfir's manufactured products a bargain on world markets, and Darfir's exports were up substantially.  Now some politicians are saying that, in order to cause another similarly sized increase in exports, the government should allow the pundra to become weak again.
Which of the following, if true, provides the government with the strongest grounds to doubt that the politicians' recommendation, if followed, will achieve its aim?
(A) Several of the politicians now recommending that the pundra be allowed to become weak made that same recommendation before each of the last two periods of currency weakness.
(B) After several decades of operating well below peak capacity, Darfir's manufacturing sector is now operating at near-peak levels.
(C) The economy of a country experiencing a rise in exports will become healthier only if the country's currency is strong or the rise in exports is significant.
(D) Those countries whose manufactured products compete with Darfir's on the world market all currently have stable currencies.
(E) A sharp improvement in the efficiency of Darfir's manufacturing plants would make Darfir's products a bargain on world markets even without any weakening of the pundra relative to other currencies.
26. (31045-!-item-!-188;#058&004365)
The population of Megacity, a sprawling metropolis in Remsland, has grown at a fairly steady rate for over a century.  A hundred years ago, poor sanitation in the city caused high mortality rates among the city's inhabitants, and what fueled the population increase was immigration from rural villages.  This immigration has continued and even increased.  Moreover, in recent decades, city sanitation has improved enormously.  Yet the city's population growth has not significantly accelerated.
Which of the following, if true, most helps to explain why the city's population growth rate has not changed?
(A) Mortality rates that were associated with poor sanitation in Megacity a hundred years ago were orders of magnitude higher than are mortality rates associated with vehicular traffic, which is currently a major cause of death in the city.
(B) For several decades, Megacity, as distinct from the countryside, has had a steadily declining birth rate.
(C) Cities smaller than Megacity have also experienced sustained population growth.
(D) The great majority of immigrants to Remsland settle in Megacity, at least initially.
(E) Megacity has long offered better employment prospects than most rural areas.
27. (31231-!-item-!-188;#058&004411)
Plant scientists have used genetic engineering on seeds to produce crop plants that are highly resistant to insect damage.  Unfortunately, the seeds themselves are quite expensive, and the plants require more fertilizer and water to grow well than normal ones.  Thus, for most farmers the savings on pesticides would not compensate for the higher seed costs and the cost of additional fertilizer.  However, since consumer demand for grains, fruits, and vegetables grown without the use of pesticides continues to rise, the use of genetically engineered seeds of this kind is likely to become widespread.
In the argument given, the two portions in boldface play which of the following roles?
(A) The first supplies a context for the argument; the second is the argument's main conclusion.
(B) The first introduces a development that the argument predicts will have a certain outcome; the second is a state of affairs that the argument denies will be part of that outcome.
(C) The first presents a development that the argument predicts will have a certain outcome; the second acknowledges a consideration that weighs against that prediction.
(D) The first provides evidence to support a prediction that the argument seeks to defend; the second is that prediction.
(E) The first and the second each provide evidence to support the argument's main conclusion.
28. (31510-!-item-!-188;#058&004526)
First-time computer buyers buying PXC home computers typically buy models that cost much less and have a smaller profit margin per computer than do PXC computers bought by people replacing their computers with more powerful models.  Last year PXC's profits from computer sales were substantially higher than the previous year, although about the same number of PXC computers were sold and the prices and profit margins for each computer model that PXC sells remained unchanged.
If the statements above are true, which of the following is most strongly supported by them?
(A) PXC's competitors raised the prices on their computers last year, making PXC computers more attractive to first-time computer buyers.
(B) The number of people buying PXC computers who also bought PXC computer-related products, such as printers, was larger last year than the previous year.
(C) Among computer buyers who bought a PXC computer to replace their existing computer, the proportion who were replacing a computer made by a competitor of PXC was greater last year than the previous year.
(D) The proportion of PXC computers bought by first-time computer buyers was smaller last year than the previous year.
(E) PXC's production costs for its computers were lower last year than they had been the previous year.

UlysessHope

【逻辑链KEY】 BBCD
【精练解释】
[attachimg=724,595]93543[/attachimg]

zz42050524

占位，今天才把6给做了~~

小意达de花儿

1. 虽然做对了，但是感觉不好，云里雾里的
LT live and breed in distinct groups: some are in PO and some are in A
Juvenile PO LT feed near B hatch in J waters 10,000 km away
95% of DNA of B turtles match DNA of J turtles
I guess: 95% is insufficient, maybe 98% of the DNA samples taken from the B turtles match those taken from A LT
(A) Nesting sites of loggerhead turtles have been found the Pacific coast of North America several thousand kilometers north of the Baja peninsula.
Irrelevant
(B) The distance between nesting sites and feeding sites of Atlantic loggerhead turtles is less than 5,000 kilometers.
Useless comparison
(C) Loggerhead hatchlings in Japanese waters have been declining in number for the last decade while the number of nesting sites near the Baja peninsula has remained constant.
This choice confused me at the first sight, but hatchlings in J have been declining in number & nesting sites near B has remained constant
(D) Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from Atlantic loggerhead turtles.
Correct, Atlantic LT live far away from the Baja Peninsula, but the similarity of DNA is also 95%
(E) Commercial aquariums have been successfully breeding Atlantic loggerheads with Pacific loggerheads for the last five years.
Irrelevant
------------------------------------------------------------------------------------------------
2. 12 years ago and 5 years ago, when D’s currency----the pundra---- was weak, the D’s exports were up substantially.
CONCLUSION: In order to gain another similarity size increase in exports, the government should allow pundra to become weak again.
I guess: think about the disadvantages; today is quite different from those days
(A) Several of the politicians now recommending that the pundra be allowed to become weak made that same recommendation before each of the last two periods of currency weakness.
I think this choice may support the argument.
(B) After several decades of operating well below peak capacity, Darfir's manufacturing sector is now operating at near-peak levels.
Correct, the manufacturing sector is at peak, even though the government weak the currency, there is no more extra increase.
(C) The economy of a country experiencing a rise in exports will become healthier only if the country's currency is strong or the rise in exports is significant.
Irrelevant, because we do not talk about the health of economy
(D) Those countries whose manufactured products compete with Darfir's on the world market all currently have stable currencies.
Irrelevant comparison
(E) A sharp improvement in the efficiency of Darfir's manufacturing plants would make Darfir's products a bargain on world markets even without any weakening of the pundra relative to other currencies.
Irrelevant, because we still don’t know what would happen, if the government weak the currency.
--------------------------------------------------------------------------------------------------------------------------------------------------
3.The population of has grown at a fairly steady rate for over a century.
100 years ago, poor sanitation in the city cause high mortality rates, and immigration from rural villages fueled the population increase
The immigration has continue and city sanitation has improved
BUT the city’s population has not increased significantly
I guess: Other reasons now cause high mortality rates(A) Mortality rates that were associated with poor sanitation in Megacity a hundred years ago were orders of magnitude higher than are mortality rates associated with vehicular traffic, which is currently a major cause of death in the city.
This choice confused me at the first sight, but we should pay attention to the word ‘currently’, however, in the original text, it is ‘recent decades’
(B) For several decades, Megacity, as distinct from the countryside, has had a steadily declining birth rate.
Correct
(C) Cities smaller than Megacity have also experienced sustained population growth.
Cannot explain
(D) The great majority of immigrants to Remsland settle in Megacity, at least initially.
Irrelevant
(E) Megacity has long offered better employment prospects than most rural areas.
Irrelevant to the employment prospects, and this choice may give more confusion why the population does not increase significantly.
--------------------------------------------------------------------------------------------------------------------------------------------------
4. Scientists have produced crop plants that are resistant to insect damage.
BUT these plants require more fertilizer and water----evidence of a conclusion, which this argument disproves.
Hence these plants cannot save money for farmers
BUT since consumer demand for pesticides-free crops is rising, the use of these seeds is likely to become widespread.----Conclusion
(A) The first supplies a context for the argument; the second is the argument's main conclusion.
(B) The first introduces a development that the argument predicts will have a certain outcome; the second is a state of affairs that the argument denies will be part of that outcome.
(C) The first presents a development that the argument predicts will have a certain outcome; the second acknowledges a consideration that weighs against that prediction.
Correct
(D) The first provides evidence to support a prediction that the argument seeks to defend; the second is that prediction.
(E) The first and the second each provide evidence to support the argument's main conclusion.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
5. Background: First-time computer buyers usually buy models that cost less and have a smaller profit margin than computers bought by people replacing their computers with more powerful models.
Last year PXC’s computer sales were higher than the previous year.
Although same number of computer were sold and prices and profit margins for each computer model that PXC sells remained unchanged.
I GUESS: this year more customers of PXC is people who want to replace their computers.
(A) PXC's competitors raised the prices on their computers last year, making PXC computers more attractive to first-time computer buyers.
If this is true, then the number of computers sole by PXC last year should increase.
(B) The number of people buying PXC computers who also bought PXC computer-related products, such as printers, was larger last year than the previous year.
Here we talk about the profits from computer sales
(C) Among computer buyers who bought a PXC computer to replace their existing computer, the proportion who were replacing a computer made by a competitor of PXC was greater last year than the previous year.
We don’t know the total number of people who by PXC computer to replace their computers
(D) The proportion of PXC computers bought by first-time computer buyers was smaller last year than the previous year.
Correct, because the total number of computer sold by PXC remained unchanged.
(E) PXC's production costs for its computers were lower last year than they had been the previous year.
The price and profit margin do not change

小意达de花儿

手打的精练题，刚才做题的时候顺便打的，楼主把这个贴上去吧
Loggerhead turtles live and breed in distinct groups, of which some are in the Pacific Ocean and some are in the Atlantic. New evidence suggests that juvenile Pacific loggerheads that feed near the Baja Peninsula hatch in Japanese waters 10,000 kilometers away. Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from turtles at the Japanese nesting sites.

Which one of the following, if true, most seriously weakens the reasoning above?

(A) Nesting sites of loggerhead turtles have been found the Pacific coast of North America Several thousand kilometers north of the Baja peninsula.

(B) The distance between nesting sites and feeding sites of Atlantic loggerhead turtles is less than 5,000 kilometers.

(C) Loggerhead hatchlings in Japanese waters have been declining in number for the last decade while the number of nesting sites near the Baja peninsula has remained constant.

(D) Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from Atlantic loggerhead turtles.

(E) Commercial aquariums have been successfully breeding Atlantic loggerheads with Pacific loggerheads for the last five years.

xeyyxzty

1.没有原题只有手打...background information: loggerhead turtles live and breed in distinct groups--Pacific/Atlantic
premise:95% of DNA samples match in the two places.
conclusion:juvenile Pacific loggerheads that feed near Baja hatch in Japanese waters
the match in DNA is not persuasive~
A--nesting sites--irrelevant
B--Atlantic loggerheads--irrelevant
C--nesting sites--irrelevant
D--so turtles are all have the match of 95%--weaken--right
E--commercial aquariums--irrelevant
2.background information:Twelve years ago and again five years ago, there were extended periods when the Darfir Republic's currency, the pundra, was weak:  its value was unusually low relative to the world's most stable currencies.  Both times a weak pundra made Darfir's manufactured products a bargain on world markets, and Darfir's exports were up substantially.  
premise: the government should allow the pundra to become weak again
conclusion: another similarly sized increase in exports
the pundra become weak and other currencies do not change-->a increase in export
what if when pundra's value decrease, other currencies also decrease their value?
or is there any change in the economic structure during the last five years?
(A) Several of the politicians now recommending that the pundra be allowed to become weak made that same recommendation before each of the last two periods of currency weakness.
--support
(B) After several decades of operating well below peak capacity, Darfir's manufacturing sector is now operating at near-peak levels.
--there is no space to have a increase in export--weaken--right
(C) The economy of a country experiencing a rise in exports will become healthier only if the country's currency is strong or the rise in exports is significant.
--irrelevant to the export
(D) Those countries whose manufactured products compete with Darfir's on the world market all currently have stable currencies.
--support
(E) A sharp improvement in the efficiency of Darfir's manufacturing plants would make Darfir's products a bargain on world markets even without any weakening of the pundra relative to other currencies.
--a improvement in the efficiency--irrelevant
OK，思路错误
3.set of facts
The population of Megacity, a sprawling metropolis in Remsland, has grown at a fairly steady rate for over a century.  
A hundred years ago, poor sanitation in the city caused high mortality rates among the city's inhabitants,
and what fueled the population increase was immigration from rural villages.  
This immigration has continued and even increased.
Moreover, in recent decades, city sanitation has improved enormously.  
Yet the city's population growth has not significantly accelerated.
Which of the following, if true, most helps to explain why the city's population growth rate has not changed?is there anything else that influence the population? such as immigration to other cities?
(A) Mortality rates that were associated with poor sanitation in Megacity a hundred years ago were orders of magnitude higher than are mortality rates associated with vehicular traffic, which is currently a major cause of death in the city.
--the population should increase
(B) For several decades, Megacity, as distinct from the countryside, has had a steadily declining birth rate.
--right
(C) Cities smaller than Megacity have also experienced sustained population growth.
--other cities--irrelevant
(D) The great majority of immigrants to Remsland settle in Megacity, at least initially.
--the population should increase
(E) Megacity has long offered better employment prospects than most rural areas.
--employment-irrelevant
4.background information(concessions):Plant scientists have used genetic engineering on seeds to produce crop plants that are highly resistant to insect damage.  Unfortunately, the seeds themselves are quite expensive, and the plants require more fertilizer and water to grow well than normal ones.  Thus, for most farmers the savings on pesticides would not compensate for the higher seed costs and the cost of additional fertilizer.  
premise:However, since consumer demand for grains, fruits, and vegetables grown without the use of pesticides continues to rise,
conclusion:the use of genetically engineered seeds of this kind is likely to become widespread.
(A) The first supplies a context for the argument; the second is the argument's main conclusion.
--right
(B) The first introduces a development that the argument predicts will have a certain outcome; the second is a state of affairs that the argument denies will be part of that outcome.
--the second--opposite
(C) The first presents a development that the argument predicts will have a certain outcome; the second acknowledges a consideration that weighs against that prediction.
--the second is a prediction--right
(D) The first provides evidence to support a prediction that the argument seeks to defend; the second is that prediction.
the first weaken the prediction
(E) The first and the second each provide evidence to support the argument's main conclusion.
--the first is not
5.background information:First-time computer buyers buying PXC home computers typically buy models that cost much less and have a smaller profit margin per computer than do PXC computers bought by people replacing their computers with more powerful models.  
premise:about the same number of PXC computers were sold and the prices and profit margins for each computer model that PXC sells remained unchanged.
conclusion:Last year PXC's profits from computer sales were substantially higher than the previous year
the number didn't change doesn't mean the percentage of each groups didn't change
(A) PXC's competitors raised the prices on their computers last year, making PXC computers more attractive to first-time computer buyers.
--there should be a decrease in profits--weaken
(B) The number of people buying PXC computers who also bought PXC computer-related products, such as printers, was larger last year than the previous year.
--computer-related products--irrelevant
(C) Among computer buyers who bought a PXC computer to replace their existing computer, the proportion who were replacing a computer made by a competitor of PXC was greater last year than the previous year.
--irrelevant
(D) The proportion of PXC computers bought by first-time computer buyers was smaller last year than the previous year.
-support--right
(E) PXC's production costs for its computers were lower last year than they had been the previous year.
--irrelevant

bananazoo

占位，晚上回来做~

qiuhua01234567

占位，今天跑了一天，待会来补
1Weaken 25S

Background：T live and breed in distinct groups，p and A

Premise：95 percent take from B match that take from T in J

Conclusion：JP feed near B in japanese water 10000 kilometer

(A) Nesting sites of loggerhead turtles have abeen found the Pacific coast of North America Several thousand kilometers north of the Baja peninsula.

--------------------------------------------------------------------------------------------------irrelevent
(B) The distance between nesting sites and feeding sites of Atlantic loggerhead turtles is less than 5,000 kilometers.

--------------------------------------------------------------------------------------------------------irrelevent
(C) Loggerhead hatchlings in Japanese waters have been declining in number for the last decade while the number of nesting sites near the Baja peninsula has remained constant.

----------------------------------------------------------------------------------------------------------irrelevent
(D) Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from Atlantic loggerhead turtles.

----------------------------------------------------------------------------------------------------------correct
(E) Commercial aquariums have been successfully breeding Atlantic loggerheads with Pacific loggerheads for the last five years.

--------------------------------------------------------------------------------------------------------------irrelevent

2.32S,weaken

1background:Twelve years ago and again five years ago, there were extended periods when the Darfir Republic
's currency, the pundra, was weak:  its value was unusually low relative to the world's most stable currencies.  Both times a weak pundra made Darfir's manufactured products a bargain on world markets, and Darfir's exports were up substantially
Premise: the government should allow the pundra to become weak again.

Conclusion: cause another similarly sized increase in exports

(A)Several of the politicians now recommending that the pundra be allowed to become weak made that same recommendation before each of the last two periods of currency weakness.
(B) After several decades of operating well below peak capacity, Darfir's manufacturing sector is now operating at near-peak levels.
(C) The economy of a country experiencing a rise in exports will become healthier only if the country's currency is strong or the rise in exports is significant.
(D) Those countries whose manufactured products compete with Darfir's on the world market all currently have stable currencies.
(E) A sharp improvement in the efficiency of Darfir's manufacturing plants would make Darfir's products a bargain on world markets even without any weakening of the pundra relative to other currencies.

1.explation 31S

background: The population of Megacity, a sprawling metropolis in Remsland, has grown at a fairly steady rate for over a century.  A hundred years ago, poor sanitation in the city caused high mortality rates among the city's inhabitants, and what fueled the population increase was immigration from rural villages

premise: This immigration has continued and even increased.  Moreover, in recent decades, city sanitation has improved enormously.

Conclusion: city's population growth has not significantly accelerated

(A)Mortality rates that were associated with poor sanitation in Megacity a hundred years ago were orders of magnitude higher than are mortality rates associated with vehicular traffic, which is currently a major cause of death in the city.

----------------------------------------------------------------------------------------------------------------correct
(B) For several decades, Megacity, as distinct from the countryside, has had a steadily declining birth rate.

---------------------------------------------------------------------------------------------------------------weaken
(C) Cities smaller than Megacity have also experienced sustained population growth.

----------------------------------------------------------------------------------------------------------------irrelevent
(D) The great majority of immigrants to Remsland settle in Megacity, at least initially.

------------------------------------------------------------------------------------------------------------------irrelevent
(E) Megacity has long offered better employment prospects than most rural areas.

--------------------------------------------------------------------------------------------------------------------irrelevnt

A是错的，只是说了主要的死亡，没有说明死亡人数巨大。Irrelevent

2.blodface 30S

(A) The first supplies a context for the argument; the second is the argument's main conclusion.
(B) The first introduces a development that the argument predicts will have a certain outcome; the second is a state of affairs that the argument denies will be part of that outcome.
(C) The first presents a development that the argument predicts will have a certain outcome; the second acknowledges a consideration that weighs against that prediction.
(D) The first provides evidence to support a prediction that the argument seeks to defend; the second is that prediction.
(E) The first and the second each provide evidence to support the argument's main conclusion.

Still confusion

3.support

background: First-time computer buyers buying PXC home computers typically buy models that cost much less and have a smaller profit margin per computer than do PXC computers bought by people replacing their computers with more powerful models

premise: PXC's profits from computer sales were substantially higher than the previous year

conclusion: although about the same number of PXC computers were sold and the prices and profit margins for each computer model that PXC sells remained unchanged.

(A)PXC's competitors raised the prices on their computers last year, making PXC computers more attractive to first-time computer buyers.

------------------------------------------------------------------------------------------------------weaken
(B) The number of people buying PXC computers who also bought PXC computer-related products, such as printers, was larger last year than the previous year.

--------------------------------------------------------------------------------------------------------irrelevent
(C) Among computer buyers who bought a PXC computer to replace their existing computer, the proportion who were replacing a computer made by a competitor of PXC was greater last year than the previous year.

aa--------------------------------------------------------------------------------------------------correct
(D) The proportion of PXC computers bought by first-time computer buyers was smaller last year than the previous year.

-----------------------------------------------------------------------------------------------------weaken
(E) PXC's production costs for its computers were lower last year than they had been the previous year.

---------------------------------------------------------------------------------------------------weaken

winghyy

精炼题
1. 〉90s（看了很久，找不到逻辑关系) -weaken
BG: L turtles live and breed in distinctive group, some in Pacific and some are in the Atlantic.
Premise: New evidence suggests that juvenile turtles that feed near BP hatch in JP waters.
Conclusion: 95% of the DNA taken from the Baja turtles match those taken from turtles at the JP.
Prephase: 完全无感。。。
D
(A) Nesting sites of loggerhead turtles have been found the Pacific coast of North America Several thousand kilometers north of the Baja peninsula.
没有提及DNA，无关
(B) The distance between nesting sites and feeding sites of Atlantic loggerhead turtles is less than 5,000 kilometers.
没有提及DNA，无关
(C) Loggerhead hatchlings in Japanese waters have been declining in number for the last decade while the number of nesting sites near the Baja peninsula has remained constant.
数量的比较，和DNA无关
(D) Ninety-five percent of the DNA samples taken from the Baja turtles match those taken from Atlantic loggerhead turtles.
提到了DNA，不过如何weaken不清楚。。。
(E) Commercial aquariums have been successfully breeding Atlantic loggerheads with Pacific loggerheads for the last five years.
Commercial aquariums无关

原来是conclusion和premise找反了
Premise: 95% of the DNA taken from the Baja turtles match those taken from turtles at the JP.
Conclusion: juvenile turtles that feed near BP hatch in JP waters 10，000 away.
选项C原来这么tricky, 都没看明白：the number of hatchlings in JP vs the number of nesting sites near the Baja
选项D weaken 说明Baja的turtle和Atlantic的turtle也share 95% DNA, 削弱

winghyy

逻辑链
25. 60s-weaken
BG:The currency of D is weak. The value of pundra was low relative to the global stable currencies.
Premise: The weak currency made the D export up.
Conclusion: some politicians suggest allow the pundra become weak again in order to cause an increase in exports.
Prephase: The weak currency will have a negative effect on the future export.
选B

26. 49s-explain
BG :The population of M remains relatively stable for over a century. 100 years ago, the population sharply declined becase of the high morality caused by the poor sanitation. What fueled the population increae was immigration from rural areas.
Premise: Now the sanitation is getting better in the city.
Conclusion: Yet the city's population growth has not significantly accelerated.
Prephase: New generation perfer to be DINKers.
选B

27.60s- boldface
BG: A new kind of plants has been developed. It is highly resistant to insect damage. Unfortunately, the saving on the peticade would not compnate for the high cost of the seeds and fertilizers.
Premise: The consumers perfer grains and vegetables without pesticides
Conclusion:The use of the seed will become widespread.
Prephase: 1st-subpremise for subconclusion
                2nd-premise and conclusion
选C （B的后半句的意思不是很清楚）

28. 55s-support
Premise: First-time users buy low-price models for PXC computers, while people who replace their computers will buy high-price models.
Conclusion: Last year PXC's profits from computer sales were higher than the previous year, although the number of PXC computers were sold  remained unchanged.
Prephase: Last year, the percentage of consumers who replaced the computer is higher than the previous year.
选D