Have you seen Ling Feng?
Yes.Why?
I've found his watch.he left it on my desk yesterday.
I'm afraid you'll have to wait.
He's gone with his group to plant trees.
Didn't he do that last month?
Yes,he did.
Why has he gone to do it again?
Why? We should plant more trees to make our city greener.
Don't you think so?
Yes,of course.The more trees,the better.
When are you going there again.
I suppose we'll go there next week.
Don't forget to tell me the time.I'd like to join you