the work that___ before building a bridge is to make a good design.

分类: 作业答案 • 2022-01-04 12:28:22

问题描述：

the work that___ before building a bridge is to make a good design.
A:must do B:is to do C：must be done Dhas been done 选什么?为什么,

答

选C
因为首先工作是被完成所以要用被动语态,就可以排除A和B.
其次这个工作并没有完成所以不能现在完成时,这样就可以排除D.