阅读对话，回答问题。(6分)
Jack：Hello，Tom.
Tom：Hello, Jack.　What are you doing now?
Jack：We are making a big zoo.
Tom：Really?
Jack：Yes.　I made a lion and a hippo.
Tom：How cute they are! Whose zebra is that?
Jack：It's Ann's.
（1）What is Jack doing?
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（2）What did Jack do?
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（3）Whose zebra is that?
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