That he wants is how to make his study better改错

that 改为 What
what引导的主语从句并在所包含的宾语从句中作主语~~
双重身份只能用what不能用that

that-what
what=the thing that

that 改成 what
由what 引导一个主语从句

把that 改成 what
因为句子的意思是,"他想要的是....."
只有"what"可以指代后面的内容

T 改成 W
(1 What) (2 he wants ) (3 is) (4 how to make his study better).
2 作定语（定语从句）
1 + 3 +4：主语+ （谓语）be + 表语。