Do you know____had reported the accident to the police?

A.who it was that 这是强调句型的特殊用法:对疑问词进行强调.
由于是用在宾从中的,因此.who要放在宾从的句首.
句意:你知道究竟是谁向警察报告了这次事故吗?为什么不能选Bwho本身就可引导宾从,再加一个that,就多余了. 并且这儿是强调"究竟是谁" ,所以正解为A.Do you know who had reported the accident to the police?这样？？Do you know who had reported the accident to the police?这个句子是对的呀!判断是否是强调句,有一个方法: 如果去掉it was... that后原句的结构及句意仍是完整的,就是强调句,反之,则不是或是错误的.选A,去掉it was... that后,句子是: Do you know who had reported the accident to the police?结构及句意仍是完整的.选B,去掉it was who后,句子是: Do you know that had reported the accident to the police?这显然不对.因此选A, 不能选B.