概念：一般过去时表示过去某个时间发生的动作或状态，常和表示过去的时间连用，yesterday，last night， in 1990，two days ago等。也表示过去经常或反复发生的动作，常和often，always 等，表示频度的时间状语连用。
例句：I got up at 6:30 yesterday. 我昨天6:30起床。
He always went to work by bus last year. 去年他总是坐公交车上班。

一般过去时的构成
一般过去时由规则动词(-ed/-d)或不规则动词的过去时表示，除be动词外，其余动词没有人称和数的变化。各种动词的否定结构和一般疑问结构，与一般现在时的否定结构和疑问结构相同。
be动词在一般过去时中的变化：
（1）am 和is 在一般过去时中变为was。 (was not=wasn't)
（2）are在一般过去时中变为were。(were not =weren't)

句中没有be动词的一般过去时的句子
●否定句：didn't +动词原形，如：Jim didn't go home yesterday.
●一般疑问句：在句首加did,句子中的动词过去式变回原形。
如：Did Jim go home yesterday.
●特殊疑问句：
（1）疑问词+did+主语+动词原形
如：What did Jim do yesterday.
（2）疑问词当主语时：疑问词+动词过去式
如: Who went to home yesterday.

规则动词过去式变化规则

情况	方法	示例
一般情况	+ed	work— worked
		look—looked
以不发音的e(哑e)结尾	+d	live —lived
		hope—hoped
		like—liked
以辅音字母+y结尾	把y变i+ed	study— studied
		carry—carried
以重读闭音节结尾且末尾只有一个辅音字母(重读辅元辅)	双写尾字母+ed	stop— stopped
		plan—planned
以ic结尾	+ked	picnic—picnicked
		traffic—trafficked
特殊情况	不规则变化	are—were
		is/am—was
		do—did
		eat—ate
		go—went
		等等

1. At the age of 16, Sam left school and started to work. (改为同义句)he 16 years old, Sam left school and started to work.

1. At the age of 16, Sam left school and started to work. (改为同义句)
he 16 years old, Sam left school and started to work.