If it doesn't rain within the next few weeks ,the crops will have to be watered if they are to be survived

问题描述:

If it doesn't rain within the next few weeks ,the crops will have to be watered if they are to be survived
这句话中有一处错误(if they are to be survived)是这一处吗
是的话错在什么地方呀!

survive 活下来的意思.
用被动语态不行,成了什么东西将要被活下来.
话的意思是,如果近几周内不下雨,我们就要给这些庄稼浇水,否则他们就死了.