Question

8. She grew up on the highland, which may explain her strong  heart  and  breathing  ability, but   really makes  her  stand  out is perseverance. 

A. that    B. what

C. which    D. why

Answer 1

8.    B考査名词性从句。but后面的分句中主语是what really makes her stand out ，谓语是系表结构is perseverance„ 主语从句中缺主语，that不能在句中充当成分；which在名词性从句中只表示疑问"哪一个"，而这个句子不表示疑问，是陈述概念。所以what相当于the thing that，故选B。