It was 1995 we began to develop the new computer system.A. whenB. whichC. sinceD. that

问题补充：

It was 1995 we began to develop the new computer system.

A. when

B. which

C. since

D. that

答案：

(答案→)A. when

B. which

C. since

D. that

解析：句意：当我们开发新的电脑系统的时候是1995年。When引导时间状语从句，it指时间，这题容易错选成D，以为是强调句，而强调句的判断方法是去掉强调结构，如果这句话还成立就是强调句，这句话去掉强调句结果后是we began to develop the new computer system1995.可以看出在1995年前面缺少介词in，所以选A。