四、过去完成时

过去完成时表示在过去某一时刻之前业已发生了的动作或现象，句中通常会出现有表示过去某一时刻的时间状语，如：

Although she law for only a little over eight years, Florence Allen became in 1922 the first woman to sit on a state supreme court.

1. will practice B)practices

C)had practiced D)has been practicing

1. 为正确答案。本句的主句有表示过去某刻的时间状语 in 1922，用的是过去时，而空白处应填入在 1922 年前已发生的动作（修习律师业 8 年多），故应使用过去完成时。

Before 1970 many technological advances in the field of computer science, which resulted in more efficient computers.

1. have been made B) made

1. make D) had been made

2. 为正确答案。因为本句明显表示过去某刻之前(before

   1970)业已发生的情况，而且又是被动语态。