There are still many problems ______ before we are ready for a long stay on the Moon. A.solving B.so...
2022-07-25 15:09:57 172次 北京市2016-2017学年高二下学期期末英语试卷 单项填空 反馈错误 加入收藏 正确率 : 100%
题目内容：
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
本题链接：
