关于动词时态的几点说明
1、一般不用进行时的动词，它们用一般现在时表示现在进行时
（1）表示心理状态的词：accept, agree, allow, believe, care, dislike, fear, forget, hate, know, like, love, mean, mind, need, prefer, realize, remember, respect, understand, want, wish等。还有 admit, decide, permit, promise, receive, refuse等。
I accept what you say. 我接受你说的话。
I don't agree to this proposal. 我不同意这个建议。
（2）感官动词和表示状态的动词一般不用进行时。系动词：如hear, look, notice, see, smell, sound, taste等词。表示状态的词：be, belong to, exist, have, remain, seem, stay等词。例如：
I see him now; he’s talking to a girl. 我看见他了，他正在和一个女孩说话。
The warships belong to the navy and the tanks belong to the army. 军舰属于海军，坦克属于陆军。
The tea tastes fresh. 这茶味道很新鲜。
It sounds strange, but it is true. 听起来很奇怪，但这是真的。
2、下列句型常用一般现在时表示现在进行时
Here/There+动词+名词主语：
Here comes the bus! 公共汽车来了。
There goes the bell. 铃声响了。
Here/There+代词主语+动词：
Here he comes! 他来了！
There he goes！ 他走了！
在make sure (certain) 后面的从句常用现在时表示将来时：
There aren’t many seats left for the concert; you’d better make sure that you get one today. 这场音乐会剩下的座位不多了，你最好今天订妥一个位子。
I’m leaving now。 -Make sure you lock the window. 我现在走了。 你务必把窗户关上。
3、将来时常用的表达方式
（1）单纯将来时用shall/will+动词原形表示。如：
I shall be twenty years old next year. 明年我就二十岁了。
Tomorrow will be September 10th. 明天是九月十号。
（2）“be going to +动词原型 ”这种形式用于人时表示打算，意图，也表示说话者确信无疑；用于物时表示可能或必然性。
They are going to get married in July. 他们打算七月份结婚。
Mr. Brown says he is going to buy a new car next year. Brown 先生说他们打算明年买辆新车。
His wife is going to have a baby. 他妻子要生小孩子了。
There is going to be a storm. 将有一场暴风雨。
Look！It’s going to snow. 看，要下雪了。
（3）“be to +动词原形 ”表示命令，安排，疑问句中表示征求意见。例如：
You are to clean the window. 你要擦窗。
The President is to arrive in Rome at three o’clock this afternoon. 总统今天下午三点到达罗马。
Am I to set to work? 要着手工作吗?
Is he to leave/come, too。 要他也走/来吗？
（4）“be about to +动词原形 ”表示即刻就要发生的动作。例如：
They are about to go out when it begins to snow. 他们正出去的时候开始下雪了.
The ship is about to sail。 船要扬帆起航了。
（5）现在进行时可表示将来。主要是表示“来，去，留，住，开始，结束 ”等意义的动词，如：come, end, leave, return, go, start, set out, meet, open, die, arrive。
We are going to Paris on Friday. We are leaving from London Airport. 我们星期五离开巴黎，我们从伦敦机场出发。
The poor dog is dying. 那条可怜的狗快要死了。
The tragedy is ending/beginning. 悲剧就要结束了/开始了。
4、现在完成时的用法
现在完成时强调的是现在的结果或影响，是个现在时态，不与明确表示过去某个时间的状语连用；常与 already, ever, lately, just, now, recently, today, tonight, yet, this week, this year, for+时间名词，in the last three years, in the past three years, so far (到目前为止)，up till now (直到现在)， up to the present (直到现在) 等包括现在在内的时间状态语连用。例如：
Where have you been this year? 今年你去过哪里。
Up to the present, great changes have taken place. 到现在已经发生了巨大变化。
Did Mary come here for a visit? She has visited China twice since 1989.
5、过去完成时的用法
过去完成时表示动作发生在过去某个时间或动作之前。如果发生有两个动作都是在过去发生的，先发生的用过去完成时，后发生的用一般过去时：
It is five years since I left middle school.（以现在为依据） 我离开中学到现在已经有五年了。
It was five years since I had left middle school.（以过去为依据） 我离开中学到那时已经有五年了。
By the end of last month they had already made 25 million dollars. 到上月底他们已经挣了两千五百万美元了。
The film had been on for minutes when he arrived at the cinema. 电影已经开始几分钟了他才到电影院。
注意：动词 expect, hope, mean, plan, suppose, think的过去完成时表示过去未曾实现的想法、希望、打算或意图。例如：
They had hoped to be able to come and see me. 他们本希望能来看我的。
I had thought to meet her there. 我想过（或我本想）在那里见她。
6、时态的呼应
时态的呼应也叫时态的一致，是指在复合句中，某些从句（主要是宾语从句等名词性从句）的时态常受主句时态的影响，因而要注意主从句两部分的时态呼应。
（1）主句是现在时态或将来时时，从句可以用任何所需要的时态。
He says his father is/was/will be a teacher. 他说他父亲是（过去是，将来要做）一个教师。
They will tell you that they are living/lived/will live/have lived in shanghai. 他们会告诉你他们正住在上海/在上海住过/将住在上海/一直住在上海。
（2）主句是过去时态时，从句的时态要注意下列几点：
A. 从句与主句动作同时发生，从句须用一般过去时或过去进行时。
I thought he studied hard. 我认为他学习努力。
He told me his son was watching TV. 他告诉我他儿子在看电视。
B. 从句动作发生在主句动作之后，从句须用过去将来时。例如：
He said he would post the letter. 他说他将要寄这封信。
They did not know when they would go to the Great Wall. 他们不知道什么时候去参观长城。
C. 从句动作发生在主句动作之前，从句须用过去完成时。例如：
He said he had posted the letter。 他说已经把信发了。
They asked me whether I had been there before. 他们问我以前去没去过那里。
但是，如果从句有具体的过去时间状语，尽管从句动作发生在主句动作之前，有时仍用一般过去时。例如：
She told me her brother died in 1960. 她告诉我她哥哥1960年去世的。
They said they checked everything yesterday. 他们说昨天他们全部检查过了。
另外，从句说的是一般真理或客观事实，即使主句用过去时态，从句仍用一般现在时。例如：
The teacher told the pupils that the earth is round. 老师告诉学生们地球是圆的。
Somebody told me you are a writer. 有人告诉我你是个作家。
除了宾语从句外，其他名词性从句（主语从句、表语从句和同位语从句）一般也要遵守这种时态呼应的规律。而状语从句和定语从句则是根据本身意思的需要选用适当的时态。例如：
He saw the boy whose mother is our teacher. 他见过那个他妈妈是我们老师的男孩。
It was not so hot yesterday as it is today. 昨天没有今天这样热。