To Chinese students who are learning English, more attention must ______ grammar.

－Did the doctors save the old man－Yes. He _______ on the morning of May 10th. And now he is out of danger.

He has recently _____ chess to provide himself with some relaxation.

form the moon, our earth with water .seventypercent of its surface, appears as a blue ball.

We were told that ______ when Marx was already _______, he started to learn Russian.