完成对话：在对话后面的句子中选出正确的填入空白处。 Jim: Excuse me, Ann. Whose black dog is this? Is it yours? Ann: Let me have a look. 1. . I think it's Sam's. My dog is brown. Jim: Sam, look at the dog behind the tree. 2. ? Sam: Sorry, it isn't mine. My dog is black and white. I think it looks like Mary's. Jim: 3. ? Sam: She's my friend. Look! She's over there. Let's go and ask her. Jim: 4. . Sam: Hi, Mary! Is that dog yours? Mary: 5. . Sam: It's a lovely dog! Don't lose it! Mary: Yes, thank you. A. Who's Mary B. OK, let's go C. Oh, no it's not mine D. Oh, yes. It's mine E. Is it yours