三道高中英语单选题,想要详解

题目

三道高中英语单选题,想要详解
6.The book was written in 1946.___the education system has witnessed great changes
A.When B.during which C.since then D.since when
7.-Do you know Anna's telephone number.
-____.As a matter of fact.I don't know any Anna,either.
A.I think so B.I'm afraid of C.I hope so D.I'd rather not
8.We haven't settled the question of___it is necessary for him to study abroud.
A.if B.where C.wheter D.that

答案

6.D.since when 作为定语从句修饰1946.因为句中给的事情是一直持续到现在的事情,现在完成时,所以选since when,如果选when,后边的句子只能用过去时.7.B.I'm afraid not委婉的否定回答,因为他都不认识叫anna的人8C.whe...