一般现在时概念和定义（一般现在时概念）

1.一般现在时　　1) 一般现在时常与often, always, usually, sometimes, everyday, once a week等时间状语连用。

　　2) 一般现在时表示客观事实或普遍真理。

　　3)第三人称单数作主语时，动词后要加-s　　标志词：often, always, usually, every day, once a week　　He takes a walk after supper every day.　　How often do you wash your hair?　　Sometimes information in the long-term memory is___ (be) hard to remember.(4B 2000 上 )　　2.一般过去时　　标志词：yesterday, last week, three years ago, in 1987　　He lived in London when he was young.　　In the l600’s，travelers from Europe_brought__ (bring) back diamonds from India.(6A 2000 上 )　　3.一般将来时　　Will (shall) + 动词原形　　Am (is, are) going to +动词原形　　Am (is, are) about to +动词原形　　Am (is, are) to +动词原形　　We’ll have to be careful in doing business with them.　　4.现在进行时　　Am (is, are) + doing　　What are you doing?　　I’m doing some washing.　　5.现在完成时　　1)现在完成时不能使用明确表示过去时间的状语，例如：yesterday, last week, in 1993等。

　　2)现在完成时可以和already, never, ever, not…yet等副词连用。

@　　3)现在完成时常和since引导的短语或从句，或由for引导的表一段时间的短语连用。

　　Have (has) + 过去分词　　I haven’t seen her since 1991.　　Have been sitting　　Has’t paid　　Had seen　　Was making　　Has been working　　Am preparing　　Has happened　　The earth goes around the sun.　　Water boils at 100 degrees.　　He does’t take a walk after supper every day.　　Does he take a walk after supper every day?　　I am a teacher.　　I am not a teacher.　　Are you a teacher?　　What’s your father?　　What does your father do?　　Be from com from　　Where is your sister from?　　Where does your sister come from?　　It rains every Wednesday.　　He goes to school by taxi every day.　　How does he go to school every day.　　What did you do 3 years ago?。