As is reported it is 100 years Qinghua University was founded.A. whenB. beforeC. afterD.

问题补充：

As is reported, it is 100 years Qinghua University was founded.

A. when

B. before

C. after

D. since

答案：

A. when

B. before

C. after

(答案→)D. since

解析：句意:正如报道的,自从清华大学成立到现在已经100年了。when 当......时候；before 在......之前； after 在......之后；since 自从。It is /has+时间段+since+sb.+did sth.自从某人做了某事已经多长时间了。故选D。