求问一道prep逻辑题。。。实在想不通。。绕不过来啊

wsw731

Comcorp Shipping Clerk:  Last week, no shipments of building supplieswere sent out on Friday.  The fivespecially ordered shipments sent out last week were sent out on Thursday, andeach of those specially ordered shipments consisted entirely of buildingsupplies.  Four shipments were sent toTruax Construction last week, none of which consisted of building supplies.
If the shipping clerk’s statementsare true, which of the following must also be true?
A. All of Comcorp’s shipments ofbuilding supplies last week were specially ordered.
B. None of Comcorp’s shipments senton Friday of last week was sent to Truax Construction.
C. None of the shipments sent byComcorp to Truax Construction last week was specially ordered.
D. None of Comcorp’s shipments senton Thursday of last week was sent to Truax Construction.
E. All of Comcorp’s shipments ofbuilding supplies last week were sent out on Thursday.
答案是C，可是我选D

还有一道更晕的大家讨论一下啦~~
Technological improvements andreduced equipment costs have made converting solar energy directly intoelectricity far more cost-efficient in the last decade. However,the threshold of economic viability for solar power (that is, the price perbarrel to which oil would have to rise in order for new solar power plants tobe more economical than new oil-fired power plants) is unchanged at thirty-fivedollars.
Which of the following, if true, doesmost to help explain why the increased cost-efficiency of solar power has notdecreased its threshold of economic viability?
A. The cost of oil has fallendramatically.

B. The reduction in the cost ofsolar-power equipment has occurred despite increased raw material costs forthat equipment.
C. Technological changes haveincreased the efficiency of oil-fired power plants.
D. Most electricity is generated bycoal-fired or nuclear, rather than oil-fired, power plants.
E. When the price of oil increases,reserves of oil not previously worth exploiting become economically viable.
这道彻底晕死。。。不知道上哪去找prep逻辑的讨论帖啊，都没有对应的题号

wsw731

有人帮我咩~~~~~~~~~

wsw731

求大NN啊

gonghao

必要条件的倒推
D是推不出来的

qiuhua01234567

conclusion: Last week, no shipments of building supplieswere sent out on Friday.
evidence:The five specially ordered shipments sent out last week were sent out on Thursday, andeach of those specially ordered shipments consisted entirely of buildingsupplies.  Four shipments were sent toTruax Construction last week, none of which consisted of building supplies.
must be true.let's simplify the clue.
five specially ordered shipments consisted of BS sent out last week. Four shipments consisted none of BS were sent
to TC last week.must be true:the answer must contain keys.
pay attention to this word:entirely.that means specially ordered shipments consisted entirely of BS have alreadly sent out on thursday.in other word,no  specially ordered  shipments consisted entirely of BS will be sent out on friday .And the shipment sent to TC.combine all informations,we can conclude that the choice(C)
rember: must be true is the the way you make clues

qiuhua01234567

必要条件的倒推
D是推不出来的

-- by 会员 gonghao (2011/11/27 22:06:45)

+1

wsw731

哦~~谢谢大牛！！

qiuhua01234567

background:Technological improvements andreduced equipment costs have made converting solar energy directly intoelectricity far more cost-efficient in the last decade.
premise:However,the threshold of economic viability for solar power (that is, the price perbarrel to which oil would have to rise in order for new solar power plants tobe more economical than new oil-fired power plants) is unchanged at thirty-fivedollars.
type of question:EVALUATION THE ARGUMENT
use "not" to test.
this sentence is important."that is, the price perbarrel to which oil would have to rise in order for new solar power plants tobe more economical than new oil-fired power plants"
let's simpify the sentence.  per barrel price the oil would have to rise in order for S more economical than O.
comparison  S VS O,now  " solar energy directly intoelectricity far more cost-efficient ",if the o also increased efficiency,then the threshold will not change.

moderatto

上周就5艘SO，且都是BS。送到TC的都没有BS，所以送到TC的一定不是SO。至于D，没有说周四就没送其他的船。

moderatto

比如说一桶油发一度电。 35刀+油设备=太阳能设备。所以35刀是两设备效率之差。与油价无关。如今太阳能设备价格降低，而35刀不变，则油设备也应该降低。所以选C。