The workers in the Huashan Mountains have to       rubbish to keep the mountains clean.

I’m having a good time __________photos. It’s interesting.

You must be very tired. Why not  ___________a rest?

It’s raining heavily. I’d rather ________ in bed ________ out.

 — You always spend only a little time on your study. You really ____       me down.— I’m sorry, Mum. I won’t do that again.