— What can we do to help animals in nature reserves?— We can .
Are you free now? I have ___________ to tell you.
There is a ______ tree in our school.
He spent a week ____ the novel.
— I broke the window. — You ____ play football near the window. A should B. shouldn’t C. had better D. must
—Must I come at four o’clock? — Oh, no, you ____.