1、Greater efforts to increase agricultural production must be made if food shortage _____ avoided.

问题描述:

1、Greater efforts to increase agricultural production must be made if food shortage _____ avoided.
A is to be B is 为什么不用B,if条件句不是可以用现在时表将来吗
2、The house belongs to my aunt but she ______ here any more.
A hasn't lived B doesn't live
为什么不用A?而用B

A. 用a因为避免饥荒是在未来,所以用to be.B. 用b因为姑姑现在不在这住了.用a说不通.