【正确答案】 D

【答案解析】[听力原文]
   W: Hi, Tom.
   M: Judy! I haven't seen you in weeks. Where have you been?
   W: In Florida.
   M: What? Vacationing while the rest of us have been studying on campus in the February cold?
   W: Not exactly. I spent most of my time underwater.
   M: I don't understand.
   W: I was on a special field trip. I went with my marine biology class.
   M: So you went scuba diving. What were you looking for, sunken treasure?
   W: You might say so. The sea is full of treasures, all kinds of strange fascinating organisms. Our class concentrated on studying plankton.
   M: I thought plankton are too small to be seen.
   W: That's a common misconception. As a matter of fact, the term Plankton covers a wide variety of freely floating plants and animals from microscopic one-celled organism to large ones such as the common jellyfish.
   M: Jellyfish may be large enough to be seen, but they are transparent, aren't they?
   W: Yes, most plankton  have transparent tissues as a way of protection. It makes them practically invisible to predators.
   M: But not invisible to your biology class, I hope.
   W: By concentrating, I was able to see the outlines of lots of different plankton. In fact, our professor even took photographs of Greeber Quadata, which are small oceanic snails.
   M: That sounds like an interesting trip. But I think if I'd been in Florida in February, I'd much rather spend my time just swimming and lying in the sun.
   W: I bet you would.
   How did Judy spend most of her time in Florida?
女士说：“我参加了一次特殊的实地调查旅行。是我们海洋生物班的同学一起去的。”由此可知答案为D。根据整个对话可知女士这段时间也一直忙于课程，而A、B、C项都表示她在“玩”，这与对话主旨不符。