功能：
（1）表示过去某个特定时间或某一段时间发生的动作或情况。
►.We visited the school last spring.
►.I went to school by bike when I was in middle school.
►.China was founded in 1949.
（2）在表示时间或条件等的状语从句中代替过去将来时。
►.She told me that she would not go with us if it rained the next day.
►.They would not leave until she came back.
►.My friend promised to marry me once she made her final decision.
一般过去时，现在时和过去时的几组差异：（别以为这很简单，下面的差异你不一定明白。）
►.Her brother was a chemist.（已去世）
►.Her brother is a chemist.（尚健在）
►.That's all I had to say.（话已说完）
►.That's all I have to say.（言之未尽）
►.It was so nice to see you.（离别时用）
►.It is so nice to see you.（见面时用）
►.Jane did a lot of work this morning.（已是当天下午或晚上）
►.Jane has done a lot of work this morning.（仍是上午）［本句现在完成时，此乃后话！］----
易口说英语
