All________is a continuous supply of the basic necessities of life.用what 和that的区别,如下

题目

All________is a continuous supply of the basic necessities of life.用what 和that的区别,如下
All________is a continuous supply of the basic necessities of life.
A．what is needed B．for our needs
C．the thing needed D．that is needed
这个选A还是 D呢 ,what 和 that 在这里有什么区别

答案

选 D that is needed
what 引导从句时,相对于 the thing that,既有先行词,又有连接词.这里已经有先行词了,所以用 that 引导