题目内容
【题目】There are still many problems ______ before we are ready for a long stay on the Moon.
A. solving
B. solved
C. being solved
D. to be solved
【答案】D
【解析】考查非谓语。非谓语的动作发生在谓语动词之后,所以要用to do,又因为非谓语的动作与逻辑主语many problems构成被动关系,所以选择to be solved。
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