In the United States, vacationers account for more

than half of all visitors to what are technically called

“pure aquariums” but for fewer than one quarter of

all visitors to zoos, which usually include a “zoo

aquarium” of relatively modest scope.

Which of the following, if true, most helps to account

for the difference described above between visitors to

zoos and visitors to pure aquariums?

(A) In cities that have both a zoo and a pure

aquarium, local residents are twice as likely to

visit the aquarium as they are to visit the zoo.

(B) Virtually all large metropolitan areas have zoos,

whereas only a few large metropolitan areas

have pure aquariums.

(C) Over the last ten years, newly constructed pure

aquariums have outnumbered newly established

zoos by a factor of two to one.

(D) People who visit a zoo in a given year are two

times more likely to visit a pure aquarium that

year than are people who do not visit a zoo.

(E) The zoo aquariums of zoos that are in the same

city as a pure aquarium tend to be smaller than

the aquariums of zoos that have no pure

aquarium nearby.

B是最佳答案。

vacationers 是度假的人。度假的人肯定是去其他城市。

而B的意思就是大多数城市都有zoos，但只有少数城市有pure水族馆。那自然是大批的度假的人来这少数的城市了。----因为本城没有嘛。

牛兄，我对这个题的理解是这样的：问题是要找到答案“most helps to account for。。。”，我对这种说法有两点认识----

1。A和B都能起到help的作用，但B所说的范围更大，更有普遍意义。

2。helps是指帮助。它只要是导致结论成立的一捆条件中的一个即可。B在这里也行，虽然也需要其它条件，例如vacationers比较平均地到大城市玩。。。。

我考虑的是A答案已经很充分了，但B答案需要其它条件的成立。

“度假的人肯定是去其他城市。”这可是没有提及的其它条件。我现在休假，就呆在家里。。。。。

还是选B。

A只是说有一些城市的情况，并不能完美解释整个国家的这个现象。

A如果把In cities that have both a zoo and a pure aquarium,换成most cities have both a zoo and a pure aquarium 就对了。

阿朗， 你理解有问题。

第一项反倒是削弱项。如果本地人都愿意去水族馆而不是动物园，那马水族馆游客的人数比动物园的游客人数多，就需要更多的度假者去水族馆，你没法证明这个。倒是如果本地人只爱去动物园，那度假者占水族馆人数比例大就可以解释了。