The reason why I burst into tears is I don’t want to part with my mother.　　　　　　A. thatB.

问题补充：

The reason why I burst into tears is I don’t want to part with my mother.

A. that

B. because

C. what

D. which

答案：

(答案→)A. that

B. because

C. what

D. which

解析：“什么样的原因”使用 The reason why...is that句型， that引导表语从句说明reason的内容，所以答案A。