【正确答案】 D

【答案解析】[听力原文]
Narrator
Listen again to part of the lecture. Then answer the question.
Professor
Now what the purple sandpiper does is, when a predator approaches, it drags its wings—but not to give the impression that its wing"s broken—but to create the illusion that it has a second pair of legs...
Narrator
Why does the professor say this?
Professor
but not to give the impression that its wing"s broken