单选题：“ Even if Sun Yang failed to kill passers-by in his car, he..

— How long do you think it will be _____ China sends a manned spaceship to the moon? — Perhaps two or three years.A. when B. until C. that D. before

My book, The House of Hales, is missing. Who ________ have taken it?A．needB．mustC．shouldD．could

Since nobody gave him any help，he ________ have done the research on his own.A．canB．mustC．wouldD．need

用所给单词的适当形式填空。 1. He was a natural leader, and when he ____ (command), everyone obeyed. 2. Theory ____ (base) on practice and in turn serves practice. 3. I am just ____ (request) that you keep him safe. 4. The girl ____ (recognize) her father and cried at

_____ you grow older, you'll know better and better about yourself.A. Since B. AsC. Before D. So