补全对话，每空一词。

A: What bad weather! The wind is blowing 1            with lots of sand. You'd better not go out now.

B: But there's 2            wrong with my computer. I want to ask Uncle Lin to mend it. Wow, what a

    strong sand storm! How 3            will it last?

A: Maybe half a day.

B: Do you know what causes these sandstorms?

A: People have cut down too many trees. But trees can prevent the sand from moving toward the rich

    land and they can also keep water from 4            the earth away.

B: So what can we do to stop the sandstorms?

A: We can 5            more trees and protect our environment.

B: I agree with you.