《专门替中国人写的英语语法》（四）
本文主要介绍“一般过去时”（the past tense）和“过去进行时”（the past continuous tense）两种时态。
一、一般过去时
一般过去时主要用于叙述过去的事，仅陈述事实；过去进行时强调某个时间点或时间段正在进行的动作。
1，一般过去时叙述过去的状态、动作或事件。（注意，这一条是最容易混淆的，也是“一般过去时”和“一般现在时”最大的不同点）
He went to Beijing the other day. （带具体时间）
I took an English class yesterday. （带具体时间）
I was a student before 2011. （过去状态，带具体时间）
2，一般过去时表示过去的习惯 （第一条和第二条是“一般过去时”最常见的用法）
1）would、used to 与过去时
would表示间断性不规则的习惯，常带频率时间
used to 表示一贯性有规律的习惯
They used to meet and would sometimes exchange one or two words. （他们过去常碰面，有时会交谈一两个字，注意would后的sometimes）
He smoked a lot two years ago. （过去的习惯）
2）would用于句中，不用于句首，表示过去的习惯；
used to 表示今昔对比的含义，叙述习惯动作，可以与would互换。
When he was a boy, he would often go there. （习惯，副词“often”）
She isn't what she used to be. （今昔对比）
3）表示状态时，一般只用used to
Tom used to be fat.
There used to stand a tree there.
4）was/were used to +ing 表示“合适于，适用于...”
He used to work at night. （他以前经常在晚上工作，规律）
He was used to working at night. （他以前习惯晚上工作，主动）
3，表示客气委婉的语气，用于情态动词，助词和want,wonder,hope等 （高级用法）
How did you like the film ?
Could you help me ?
二、过去进行时
1，表示在过去某阶段或某一时刻正在发生
What were you doing at 8:30 last night ?
2，短暂性动词用过去进行时表示“按计划...”，“打算...”
During that time he was going with us. （打算）
3，与频率词，如often,always,usually等连用，表示喜爱，讨厌等情感。 （高级用法）
He was always changing his mind.
三、区别
1，进行时表示某一行为的“片段”；一般时表示某一行为的“整体”和存在的状态。
I was reading the book at that time. （强调参考时间段的动作）
I read the book yesterday. （陈述事实，强调结果或状态，“这本书我昨天读过了”）
2，一般持续时间状语多与进行时连用
It was raining all night. （优先用进行时，不过rained为持续动作，也可以用）
He was writing a letter the whole of aternoon. （持续时间状语，本句不可用一般过去时）
3，when状语从句，描述过去的多件事，主句用过去进行时，从句用一般过去时
It was raining when he went to school yesterday. （实际上，从句是参考点）
He was reading newspaper when the train stopped.
I was brushing my teetch when my father called me.
4，while状语从句包含短暂性动词时，只能用进行时
He broke the chair while he was jumping up and down.
5，while所在主从句动作大致持续相等时，主从句一般都用进行时；两个动作持续时间一长一短，短的用一般过去时，长的用过去进行时。
I was cooking the dinner while he was playing the piano. （并列）
I saw him while I was walking to the station.
注：while 和 when 刚好相反。
四、英语中有四类动词不用进行时（现在进行时和过去进行时）
1）表心理、情感的动词。
love,like,care,hate,respect,please,prefer,know等
2）表存在和状态的动词
appear,exist,lie,remain,stand,seem等
3）表感觉的动词
see,hear,feel,smell,sound,taste等
对应：watch,listen,share,...
4）表一时性的动词
accept,allow,admit,decide,end,refuse,permit,promise等。
Exercise:
1，As she was reading newspaper, Granny fell asleep.
短暂动作和持续动作
2，Tom slipped into the house when no one was looking.
3，Is Smith in America ?
Yes,he was living in China for these years.
4，The method he had stuck to was proved right.
Explaination: stick to something, stuck
5，Tom burnt his hand when he was cooking dinner.
