－We can’t achieve our dream we keep hard.－I agree with you.

Recycling is one way to protect the environment; reusing is ___.

What’s wrong with you, Jack You look tired.—I ________ to prepare for the final exam last night.

Have you ever to Beijing—Yes. I there with my son last year.

I ______have come here in time, but I met an old friend of mine. I stopped and talked with him for some time.