The TV play is about a true story ___happened in Mianyang in 1998a it b what c that d when 理由啊
问题描述：
The TV play is about a true story ___happened in Mianyang in 1998
a it b what c that d when 理由啊
答
1,先判断这是个定语从句,先行词是a true story,从句缺少主语成分,后面需要一个定语从句的引导词,既起连接前后句子的作用又充当从句主语.
2,若选a,it就成了两个句子,中间却没有连接词and,所以不对.b,what不是定语从句引导词,c,that是对的,作主语,代指 a true story ,同时引导后面 -happened in Mianyang in 1998.这个句子
d,when可以引导定语从句,但是只能充当时间状语成分,而句子中有完整的状语 in 1998.故排除.