在对话的空白处填上适当的句子，使对话意义完整，语法正确。

A: Hi, Xiao Peng, long time no see. 1_______?

B: I have been to my hometown.

A: 2_______?

B:Yes. But I felt a little sad.

A: 3_______?

B: I saw many kinds of pollution in my hometown.

A: 4_______?

B: Yes, first, the water pollution. In the past,the water in the river was clean and there

     were a lot of fish in it.But now the water is very dirty.

A: Oh, it's a great pity.

B: Second, I can see white pollution everywhere.

A: I think we should do something for your hometown.

B: Thanks. The local government has done something to protect the environment.

A: Good, 5_______?

B: Yes, I will. I want to see what I can do for it.

A: OK. Let's join hand.