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.