问题补充:
Many people wrote articles on Liu Xiang had failed to compete in the event .
.
A. why
B. what
C. who
D. that
答案:
(答案→)A. why
B. what
C. who
D. that
解析:“Liu Xiang had failed to compete in the event .”做介词on的宾语,宾语从句中不缺主干,故排除B.和C.。另外that不引导介词的宾语从句(固定搭配除外),所以排除D. that