【正确答案】 D

【答案解析】[听力原文]15-18 W: Wasn't that a terrific lecture on dolphins? I didn't know that dolphins traveled in such large groups, or were able to communicate with other members of their group with those whistle-like sounds. M: And they also use clicks as a sort of sonar. W: I really couldn't understand that part of the lecture. You could? M: Yes, the dolphins use clicks to identify objects in the water; they can even identify tiny objects more than 100 meters away using these clicks. Scientists believe that a dolphin may even have a sonar-like image in its brain of a distant object so that it can identify the object long before the dolphin can actually see the object. W: So the dolphins use these clicks mostly to identify objects in the water? M: I think so, and they have considerably more ability to do this than humans do. W: It is hard to believe that, in addition to these sonar clicks, dolphins are actually learning some human language. M: Yes, I believe that the lecture said that some dolphins had already learned around fifty human commands, and that those dolphins were able to understand not only individual words but words clustered together in sentences! W: Dolphins must certainly be amazing animals to do all of that. M: I'm sure they are, and we're only just beginning to find out how intelligent they are. 对话中第一句话女生说：“Wasn't that a terrific lecture on dolphins?”(“多好的关于海豚的讲座呀”)，可以判断出她关于海豚的知识正是从这堂讲座中学到的。所以答案选择D项。

【正确答案】 B

【答案解析】对话中男生说“the dolphins use clicks to identify objects in the water”，说明海豚使用敲击在水中辨识物体。所以选择应当选择B项。

【正确答案】 C

【答案解析】这是一道细节题，根据男生介绍“I believe that the lecture said that some dolphins had already learned around fifty human commands”，可以知道一些海豚已经学会了约50种人类指令。所以答案应选择C项。

【正确答案】 D

【答案解析】对话中最后一句话表明了男生对海豚智商的态度：“We're only just beginning to find out how intelligent they are．”意思是“我们刚刚开始了解海豚有多聪明”，言外之意，海豚比我们知道的还要聪明得多。所以选择答案D项。