If nothing______, the oceans will turn into fish deserts.

_______________ both like playing basketball very much.

Has your father returned from Africa yet?—Yes, but he _____ here for only three days before his company sent him to Australia.

Up to now, the poet has written eight poems, three ___ are about American country life.

You _____ the meeting to tell me that. You could have come up to me afterwards. [ ]