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

A.He

B.It

C.That

D.What

答案及解析： D

解析：

句首的What is hard是主语从句，注意What is hard后的谓语动词is，假若没有后面的is，则应选B，即说成：It is hard to do well all one’s life and never do anything bad．C项作连接词时在句中没有意义。A项在句中不符的原因是hard不是he本身的特征。