一，一般现在时
1，表示经常发生的事情或者经常存在的动作或状态
例如： She sings with the band Crazy Boy.
I teach English.
$常与 always, usually, often, sometimes, every day, every week等时间状语连用。
例如： She is often late. He goes to work every day.
2,表示内心活动感情等。
例如： I know. I think that's a good idea.
I want your help. I don't think you are right.
3，描述客观真理。
例如： The sun rises in the east and sets in the west.
The earth is round. Birds fly in the sky.
4,表示预定的行为。
例如： The train leaves at 9 am.
二，一般过去时
1，表示过去发生的事情或者存在的状态
例如： Suddenly, the clouds cleared and the rain stopped.
2,表示过去经常发生的事情
例如： I was very thin in my childhood.
3,带有确定的过去的时间状语： last year, two days ago, just now, yesterday, in the old days,等
例如： Did you meet yesterday?
He left just now.
三，现在进行时
1，表示正在发生的事情或行为(常与 now连用)
例如： We're having a meeting.
I'm watching TV.
2,表示现阶段正在发生的事情。
例如： He is writing a book these months.
3,点动词(非延续性动词)不表示进行，而表示将来( come, go, arrive, leave, return...)
例如： My brother is coming tomorrow.
I'm leaving.
四，过去进行时
1，表示过去某一时间或某段时间正在发生的事情或动作
例如： When I arrived, it was raining.
2,过去进行时，一般要有一个过去的行为或时间为参照
例如： I was having breakfast when he tepephoned me yesterday.
What were you doing at eight o'clock yesterday?
五，一般将来时：表示将来的动作或状态
例如： In the future, there'll be a new school.
My mother is going to spend her holiday in Shanghai in August.
两种标志： will/ shall与 be going to的区别
will表示有计划的，计划好的
be going to表示没有计划的
例如： There is sb at the door, I'll go and open it.
He is going to change his job.
六，现在完成时：它跨在两个时间上，一个是过去，一个是现在。动作发生在过去，对现在有影响。而且句子重点在对现在的影响上。
1，表示过去的行为对现在的影响(常与 already, ever, just, never, yet等连用)
例如： I've written down some ideas.
LiMing has just turned off the light.(强调现在灯关了)
2，表示一个动作从过去开始一直持续到现在，并有可能还会延续下去
例如： I have lived here for a long time.
He has been ill for a week.
七，点动词不与表示一段时间的时间状语连用
例如： I have bought this book.( buy为点动词，不可与段时间状语连用)
I have had the book for two months.( had是 have的过去分词，是延续性动词，在这当保持，拥有讲，可以同段时间状语连用)
I left Shanghai 3 days ago
I've been away from Shanghai for 3 days.(同理上例)
