听力原文：M: Hi, Claire. How does it feel to be back on campus? W: Keith, hi. Well, to tell you the truth, I have mixed feelings. M: Oh, why? W: I had this great summer job that I really hated to leave. I worked at the Wildlife Research Center in Maryland. M: That makes sense for a genetics major. What did you do? Clean the cages? W: It is a wildlife center, not a zoo. The place breeds endangered species and tries to prepare them for life in the wild. M: You mean the endangered species like the tiger and the panda? W: Well, endangered species, yes. But not tigers or pandas. I was working with whooping cranes and sandtail cranes. It was really neat. I taught the baby cranes how to eat and drink, and I helped the vet give medical check-ups. M: I can see why it was hard to leave the job. But how did you teach a bird how to eat and drink? W: We covered ourselves up with clothes and used puppets made out of stuffed cranes to show the baby chicks what to do. Then the chicks copied what the puppets did. M: Clothes? Puppets? Sounds like fun. W: It was. The clothes and puppets were all key tools of this. We all covered ourselves up, the scientists, the vets, the junior staff, everybody. You see, baby cranes will become attached to their care-takers. M: So if the care-taker is a person, the crane will stay in places where people are. W: Yeah. And their chances for survival aren't good. But by covering ourselves up and by using bird puppets the chicks are more likely to seek out other birds rather than people. And their transition to the wild has a better chance of being successful. M: A chance of being successful? Hasn't this been done before? W: It's been done with sandtail cranes and everyone is optimistic about it working with whooping cranes, too. M: Yeah. It's exciting, isn't it? (20)