we have achieved all that we expected.句子中为什么用that呢?可以用what不?

we have achieved all that we expected.句子中为什么用that呢?可以用what不? We have achieved great progress.______,we are confident that I have a dream that one day we could meet这句话中,关系代词为什么用that而不 the problem is that we are late.中that为什么不能换成what,可以讲一些基本的句子成 That they passed the exam was what we had expected这个句子怎么分析 That they won the game was what we had expected all that we have is what we have done for others. All that we have to do is to practise everyday.能否将that改为what we all know the news ( that ) he told her,为什么不能填what,填了what不 We have each other,that's all that (that's all that we have left)这个神马意思、、 we could have had it all为什么不直接用have it all?