详细说明为什么.

题目

详细说明为什么.
More trees ______ on the hill .
A,must be planted B,be planted C,can plant D,should plant
We _______ shanghai for two days
A,have been away B,have be away from C,have been away from D,had been away from
what time do you ______ nanning
A,reach to B,get C,arrive D,reach

答案

A 是树被种在山上,排除C、D 而B不可以直接用be 应该用are
A 我们离开上海已经两天了 be away 有离开的意思 此句子是完成时
A get、arrive 后面要加to