阅读对话, 选择正确的答案。

Zhang Peng: Look! Tomatoes．        

Jack: Wow, they're yellow．

Zhang Peng: Yes．But they're good．

John: What are these?

Zhang Peng: They're green beans． 

John: They're so long．

Amy: Are these carrots?             

Zhang Peng: No．They're potatoes．