文档介绍：时态
一般现在时
一般现在时表示将来时间，往往用在时间状语从句或条件状语从句中，也就是我们经常说的“主将从现”。
If she doesn’t tell him the truth now, he’ll simply keep on asking her until she______. (CET4-9806)
does B. has done C. will do D. would do
现在进行时
现在进行时表示现阶段正在进行的动作
Mr. White works with a chemicals import & export company, but he____ for this industrial fair, since he is on leave. (TEM4-1997)
has worked B. works C. has been working D. is working
②现在进行体表示感情色彩
现在进行体常与always, continually, constantly, perpetually, forever等，表示“总是”、“继续不断地”等频度状语连用，带有浓厚的感情色彩，表达说话人不满、不耐烦等情绪。
How can I ever concentrate if you____ continually____ me with silly questions? (TEM4-1997)
have…interrupted C. are…interrupting
had…interrupted D. were…interrupting
③ be+being + 形容词
状态动词be的进行时态(be being)后面接行为形容词brave, careful, stupid, clever, foolish, polite, kind和shy等，表示主语所表现的非一贯性特点或故意的行为或暂时出现的平时所没有的某种特质。
He is being a good boy today.
He is being polite.
将来时的几种特殊表达形式
be +going to+动词原形，表示即将发生的或最近打算进行的事，一般不用于含有条件或时间状语从句的主句中。
We are going to have a meeting this afternoon.
be + to +动词原形，表示按计划要发生的事或征求对方意见 (真2)
Are we to go on with this work?
be about to+动词原形，表示即将发生的动作，意为“很快，马上”，后面一般不跟表示明确的将来时的时间状语
Mrs. Brown was about to leave when the phone rang.
一般过去时和现在完成时的区别
都表示过去完成的动作，但现在完成时着重强调过去动作与现在的关系，即对现在产生的结果或影响等，而一般过去时只表示过去某一时刻发生的动作，不表示和现在的关系。
I have lost my bike. (我丢了自行车，现在还未找到)
I lost my bike yesterday. （我昨天丢了自行车，现在是否找到没说明）
现在完成时可表示持续到现在的动作或状态，一般用延续性的动词live, work, study, teach, learn, know 等；而过去时常用于非持续性动词，如become, die, finish, get, come, leave等
His father died two years ago. 他父亲两年前过世了
His father has been dead for two 。
现在完成时与现在完成进行时的区别
现在完成时表示动作已经完成，现在完成进行时常常表示动作仍在进行中或未完成
She has painted a picture.
She has been painting a picture.
现在完成时往往只说明一个事实，一种影响或结果；现在完成进行时有时含有明显的感情色彩
I’ve been waiting for three hours. (带有不满的感情色彩)
I’ve waited for three hours.
时态的一致
如果主句的谓语动词为现在时或将来时，从句中的谓语动词应该用什么时态就用什么时态
She knows you have been in Bei