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。