newbie求助逻辑解析~~~~~求助啦~~~

旺财财

求助寄到逻辑题，看答案还是 不太懂，求助啦~~~


4.        (24323-!-item-!-188;#058&000813)

A popular beach has long had a dolphin feeding program in which fish are given to dolphins several times a day; many dolphins get as much as half of their food each day there.  Although dolphins that first benefit from the program as adults are healthy and long-lived, their offspring have a lower life expectancy than offspring of dolphins that feed exclusively in the wild.

Which of the following, if true, most helps to explain the lower life expectancy of offspring of dolphins feeding at the beach compared to other young dolphins?

(A) Sharks that prey on dolphins are less common in the open seas off the beach than in many other areas of the open seas where dolphins congregate.
(B) Many of the adult dolphins that feed at the beach are females that nurse their offspring there.
(C) The fish given to the dolphins at the beach are the same types of fish that dolphins typically catch in the wild.
(D) Many dolphins that feed at the beach with their offspring come to the beach only a few times a month.
(E) Adult dolphins that feed at the beach spend much less time teaching their offspring how to catch fish in the wild than do other adult dolphins.
这道答案是E。

5.        (24371-!-item-!-188;#058&000859)

Tiger sharks are common in the waters surrounding Tenare Island.  Usually tiger sharks feed on smaller sharks, but sometimes they have attacked tourists swimming and surfing at Tenare's beaches.  This has hurt Tenare's tourism industry, which is second only to its fishing industry in annual revenues.  In order to help the economy, therefore, the mayor of the island has proposed an ongoing program to kill any tiger sharks within a mile of the beaches.

Which of the following, if true, most strongly calls into question the likelihood that implementation of the mayor's proposal will have the desired consequence?

(A) Even if not all the tiger sharks that come close to the beaches are killed, the existence of the program would reassure tourists.
(B) Business owners who depend on tourism are willing to pay most of the cost of implementing the program.
(C) Tourists come to Tenare Island for its beaches, even though the island features a number of other tourist attractions.
(D) The small sharks on which tiger sharks prey feed on fish that are commercially important to the island's fisheries.
(E) Not all tourists who come to Tenare Island enjoy swimming or surfing.
这道题答案是D，让我很惊讶~~~~因为有点说不通的样子。

12.        (25359-!-item-!-188;#058&001894)

Finding of a survey of Systems magazine subscribers:  Thirty percent of all merchandise orders placed by subscribers in response to advertisements in the magazine last year were placed by subscribers under age thirty-five.

Finding of a survey of advertisers in Systems magazine:  Most of the merchandise orders placed in response to advertisements in Systems last year were placed by people under age thirty-five.

For both of the findings to be accurate, which of the following must be true?

(A) More subscribers to Systems who have never ordered merchandise in response to advertisements in the magazine are age thirty-five or over than are under age thirty-five.
(B) Among subscribers to Systems, the proportion who are under age thirty-five was considerably lower last year than it is now.
(C) Most merchandise orders placed in response to advertisements in Systems last year were placed by Systems subscribers over age thirty-five.
(D) Last year, the average dollar amount of merchandise orders placed was less for subscribers under age thirty-five than for those age thirty-five or over.
(E) Last year many people who placed orders for merchandise in response to advertisements in Systems were not subscribers to the magazine.
这道说实话，理解上有点绕~~~大神们不要介意小白的incompetence~~~~
求助到这里，请大牛们不吝赐教~

山贼的头头

第一题是说E成年海豚不教幼年捕鱼，因此他们的捕鱼能力差，所以导致数量减少。很显然选这个。
第二题是说既然捕鱼业是第一大产业，那么所捕的鱼不可能没有。因此以这些鱼为生的小鲨鱼也不可能不存在.因而即使现在消灭了虎鲨，小鲨鱼的存在还是会吸引他们来的。
第三题。。。老遇到的题了。subscriber<>people

旺财财

山贼的头头 发表于 2014-7-2 00:19
第一题是说E成年海豚不教幼年捕鱼，因此他们的捕鱼能力差，所以导致数量减少。很显然选这个。
第二题是说既 ...

晕。第二题还要想到小鲨鱼。真没想到这一层    thank u  anyway