SECTION A CONVERSATIONS Directions: In this section you will hear several conversations. Listen to the conversations carefully and then answer the questions that follow. 听力原文：Judy: Hi, Tom! Tom: Judy. Haven't seen you in weeks. Where have you been? Judy: In Florida. Tom: (9[C]) What, going On holiday! While the rest of us are studying on the campus in February cold? Judy: Not exactly. I spent most of my time under water. Tom: I don't understand. Judy: (10[A]) I was on a special field trip. I went with my marine biology class. Tom: So you went diving. What were you looking for, sunken treasure? Judy: You might say so. The sea's full of treasures. All kinds of strange fascinating organisms. Our class concentrated on studying plankton. Tom: I thought planktons were too small to be seen. Judy: That's common misconception. The term plankton covers a wild variety of freely flowing plants and animals, from one cell organisms to larger ones, such as the common jellyfish. Tom: Jellyfish may be large enough to be seen. But can you see the very tiny planktons? Judy: By concentrating. I was able to see the outlines of lots of different plankton plants and animals. Tom: That sounds like an interesting trip. But I think if I've been in Florida in February, I'd much rather spend my time just swimming and lying in the sun. What was Tom doing in February?