It is ten years ____ we saw each other again 选A. 这句应翻译为, 我们没见面已十年了. 原因如下: since+从句 有两种情况, 1. 从句用延续性动词,理解为从句的反意,即上面的"没见面". 又如: It is 5 years since I lived in Taiyuan. 我＿不在＿太原居住已５年了． ２.从句用短暂性动词,理解为从句的正意． 如:It is 5 years since I came here. 我＿在＿太原居住已５年了. 本题的考查重点就是以上所说．before 不能这么用．因为before引导时间状语从句，从句用了过去时，主句也得相应用过去时．ＯＫ？这题的确有难度．但只是个是否了解的问题．
b
此题答案选A。 since可用于下面的句子中。 It is a long time since something happened. 比如：It is two years since I last saw John.(I haven't seen John for two years.)我已两年没见到约翰了。 这样的句子都是以过去的某个时间作为起点，延续至今。如果把主句改成过去时，则要去before。如： It was ten years since we saw each other again. 很感谢楼下的回答，让我对这道题有了一个新的认识。我想，楼主就选我下面这位兄弟的答案吧。
A
可乐的海洋说得对
since的四种用法 1) since +过去一个时间点 (如具体的年、月、日期、钟点、1980, last month, half past six)。 I have been here since 1989。 2) since +一段时间+ ago I have been here since five months ago。
3) since +从句 Great changes have taken place since you left。 Considerable time has elapsed since we have been here。
4) It is +一段时间+ since从句 It is two years since I became a postgraduate student。 这个题目就是属于第３ 个情况。选A。
A...
答：选D 此题主要难在Ａ．Ｄ 选项 填that是不符和语法的，它不是一个强调句，一般判断强调句的方法是： 如果将句中的It is/was．．．that...去掉后...详情>>
