— The yard is so clean today and everything looks fine.

—Yes. It，s clear that someone　　　 it.

A. cleans　　 B. cleaned　　　 C. has cleaned D. was cleaning

The yard is very dirty. Let's ________ .

A. to clean up it

B. clean up it

C. to clean it up

D. clean it up

–Would you mind _______ the yard?

–OK. I’ll do it in a minute.

A. clean             B. cleans          C. cleaning          D. to clean