Question

【题目】 (2014·北京)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

Answer 1

【答案】D

【解析】句意：在我们准备好长久待在月球上之前还有很多问题需要解决。分析句子可知所填部分作problems的定语，problem和solve之间是被动关系，排除A项；再根据句意可知这些问题还没有解决，因此动作还未发生，排除B、C。故选D。