is hard is to do good all one’s life and never do anything bad.A. ThatB. WhatC. AllD. Whic

问题补充：

is hard is to do good all one’s life and never do anything bad.

A. That

B. What

C. All

D. Which

答案：

A. That

(答案→)B. What

C. All

D. Which

解析：句意：难做的事情是人的一生都做好事，从不做坏事。第二个is前面的是主语从句主语从句中缺少主语，用what连接，that连接主语从句的时候，不做成分，all后面加that就对了，which引导定语从句，所以选B。