A、 They wanted to follow his example.
B、 They fully supported his undertaking.
C、 They were puzzled by his decision.
D、 They were afraid he wasn't prepared.

【正确答案】 C

【答案解析】解析：短文一开始就提到“当我把兴趣从太空转向海洋的时候，我从未想到这会使朋友们感到如此困惑，然而我能够理解他们的感受。”C的puzzled对应短文中的confusion，语义相同，所以选C。

A、 It is more exciting than space travel.
B、 It is much cheaper than space travel.
C、 It is much safer than space travel.
D、 It is less time-consuming than space travel.

【正确答案】 B

【答案解析】解析：短文提到，“我”转移兴趣的第一个原因就是经济方面的，水下探险比太空飞行要便宜得多。只有B符合。

A、 They both attract scientists' attention.
B、 They both can be quite challenging.
C、 They are both thought-provoking.
D、 They both lead to surprising findings.

【正确答案】 B

【答案解析】解析：短文提到，出人意料的是，海洋与太空有许多共同之处，对于人类来说，海洋和太空同样不友好，如果要在其中生存，必须借助器械的帮助。B“它们都挺有挑战性的”是对原文的概括，故选B。

A、 To show how simple the mechanical aids for diving can be.
B、 To provide reasons for his changeable character.
C、 To explore the philosophical issues of space travel.
D、 To explain why he took up underwater exploration.

【正确答案】 D

【答案解析】解析：主旨题。在听完整篇短文及回答完以上三个问题之后，可以发现大部分篇幅都是用来解释作者为什么对underwater exploration(水下探险)发生了兴趣。所以选D。