1 一般现在时的用法
1) 经常性或习惯性的动作，常与表示频度的时间状语连用。时间状语： every…, sometimes,ofen,always,usually, twice a week, at…, on Sunday
I leave home for school at 7 every morning. He watches Tv once a week .
2) 客观真理，客观存在，科学事实。
The earth moves around the sun. Shanghai lies in the east of China.
3) 表示格言或警句中。 Pride goes before a fall.骄者必败。
注意：此用法如果出现在宾语从句中，即使主句是过去时，从句谓语也要用一般现在时。
例：Columbus proved that the earth is round..
4) 现在时刻的状态、能力、性格、个性。
I don want so much. Ann Wang writes good English but does not speak well.
比较：Now I put the sugar in the cup.I am doing my homework now.
第一句用一般现在时，用于操作演示或指导说明的示范性动作，表示言行的瞬间动作。再如：Now watch me, I switch on the current and stand back. 第二句中的now是进行时的标志，表示正在进行的动作的客观状况，所以后句用一般现在时。
二. 构成及变化 1、be动词的变化
肯定句：主语+be(am,is,are)+其它。如：I am a boy.我是一个男孩。
否定句：主语+ be + not +其它。如：He is not a worker.他不是工人。
一般疑问句：Be +主语+其它。 如：-Are you a student?-Yes. I am. / No, Im not.
特殊疑问句：疑问词+一般疑问句。如：Where is my bike?
2、行为动词的变化 当主语为第一，二人称及复数时，助动词为do
肯定句：主语+动词原形(+其它)。如：We often play basketball after school.
否定句：主语+ don +动词原形(+其它)。如：we don’t play basketball after school.
一般疑问句：Do +主语+动词原形+其它?如：Do you often play basketball after school l? Yes, we do. / No, we don .
2 一般过去时的用法
1）在确定的过去时间里所发生的动作或存在的状态。
时间状语有：yesterday, an hour ago, the other day, in 1982 yesterday morning (afternoon, evening…)last night (week, month, year…),a moment ago , a week ago, three years ago…just now,等。 Where did you go just now?
2）表示在过去一段时间内，经常性或习惯性的动作。
3）句型：
It is time for sb. to do sth "到……时间了" "该……了"
It is time sb. did sth. "时间已迟了" "早该……了"
It is time for you to go to bed. 你该睡觉了。
It is time you went to bed.你早该睡觉了。
would (had) rather sb. did sth.表示宁愿某人做某事
Id rather you came tomorrow.
4) wish, wonder, think, hope 等用过去时，作试探性的询问、请求、建议等。
I thought you might have some. 我以为你想要一些。
比较：一般过去时表示的动作或状态都已成为过去，现已不复存在。
Christine was an invalid all her life.
(含义：她已不在人间。)
Christine has been an invalid all her life.
(含义：她现在还活着)
Mrs. Darby lived in Kentucky for seven years.
(含义：达比太太已不再住在肯塔基州。)
Mrs. Darby has lived in Kentucky for seven years.
( 含义：现在还住在肯塔基州，有可能指刚离去)
注意： 用过去时表示现在，表示委婉语气。
1）动词want, hope, wonder, think, intend 等。
Did you want anything else?
I wondered if you could help me.
2）情态动词 could, would. Could you lend me your bike?
3 used to / be used to
used to + do："过去常常"表示过去习惯性的动作或状态，但如今已不存在。
Mother used not to be so forgetful.
Scarf used to take a walk. (过去常常散步)
be used to + doing： 对……已感到习惯，或"习惯于"，to是介词，后需加名词或动名词。
He is used to a vegetarian diet.
Scarf is used to taking a walk.(现在习惯于散步)
