Whenever I met him was fairly often I like his sweet and hopeful smile.A. whatB. thatC.

问题补充：

Whenever I met him, was fairly often, I like his sweet and hopeful smile.

A. what

B. that

C. which

D. when

答案：

A. what

B. that

C. which

D. when

解析：非限制性定语从句不用that，而应该使用which。本题中的which指代整个主句的内容。