The doctor advised Vera strongly that she should take a holiday but didn’t help.A. it B.

问题补充：

The doctor advised Vera strongly that she should take a holiday, but didn’t help.

A. it

B. she

C. which

D. he

答案：

A. it

B. she

C. which

D. he

解析： it指代前文提到的事情，如果把but去掉则成了非限制性定语从句，用which。