Harry Potter fans were left in shock author JK-Rowling revealed she regretted pairing Gra

问题补充：

Harry Potter fans were left in shock author J．K-Rowling revealed she regretted pairing Granger and Ron in the novel．

A. what

B. when

C. since

D. before

答案：

A. what

(答案→)B. when

C. since

D. before

解析：句意：当作者J．K-Rowling披露她后悔在小说中让Granger 和 Ron成为一对的时候，哈利波特的粉丝很惊讶。这里需要when引导时间状语从句，“当…时候”，what“什么”，since“自从”before“在…前”，都不符合句意。所以选B。