英语从句中用all that=what.
两者之间可以替换.但两者之间有差异,因此意思上也有差异.
"all"指你所提及的事物外再无其他的东西.而“what”是指特定的/具体的事物,如:What you need is a good long holiday.又如：What annoys me is the way he boasts about what he's done.