I just can not be believe ____ he said in such a situation.(that which what when)

问题描述:

I just can not be believe ____ he said in such a situation.(that which what when)

楼主是打错了么?怎么会在believe前还有个be呢?
应该用what,首先believe后是一个宾语从句,what 在从句既中作宾语也作主语,表示“他所说的话”;that只起连接作用没有实际意义;which不能引导宾语从句;when同样不引导宾语从句,而且放在此句中句意不通.故选what