Robert is said _______ abroad, but I don’t know what country he studied in.
—It is strange that Dave didn’t respond________any of my emails.—Something must have happened to him.
Too much drinking will do________to your health;you should take the doctor’s advice.
—How long have you________?—It is about ten years since we________.
Tom is ___________ that he can’t go to school.
With the development of science and technology,there is no doubt_____Chineseastronauts will land on the moon in the near future.