時態

英語共有9種時態，主要有：
一般時態——現在式、過去式、未來式；
完成式態——現在完成式、過去完成式、未來完成式；
進行式態——現在進行式、過去進行式、未來進行式；

時態	規則	範例
現在式	V	learn
過去式	Ved	learned
未來式	will + V	will learn
現在完成式	have + Ved	have learn
過去完成式	had + Ved	had learn
未來完成式	will have + Ved	will have learn

現在式
表示不變的事實

The moon moves round the earth.

The sun rises in the east and set in the west.

Heaven helps those who help themselves.

The teacher said that the earth is larger than the moon.

現在式表示沒有時限的持久存在的動作或狀態或現階段反復發生的動作或狀態，常和副詞 usually，often，always sometimes， regularly，near，occasionally，every year, every week 等連用。
Mr. Smith travels to work by bus every day.

He often goes to the church on Sundays.

在 由after，until，before，once，when，even if，in case，as long as，as soon as，the moment 以及 if，unless 等引導的時間子句或條件子句中，通常用一般現在式代替未來式。例如：
I will tell him the news as soon as I see him.
I will not go to countryside if it rains tomorrow.
I will have arrived by the time the meeting begins.

某些表示起始的動詞，可用一般現在式表示按規定、計畫或安排要發生的動作，這類動詞有：be，go，come，start，depart，arrive，begin，leave 等。例如：
The plane leaves at three sharp.
The new teachers arrive tomorrow.

在由why，what，where，whoever，who，that，as 等引導的子句中，也常用一般現在式代替未來式。例如：
Free tickets will be given to whoever comes first.
You will probably be in the same train as I am tomorrow.

過去式
過去的事實

The Korean War broke out in 1950.

Her son entered the college last year.

He ask me when Caesar invaded England.

表示過去某一特定時間所發生的、可完成的動作或狀態，常與表示確切過去式間的詞、短語或子句連用。如 yesterday, last year, in 1949, a minute ago, just now例如：
We went to the pictures last night and saw a very interesting film.

He went to the station yesterday.
I met the man three years ago.

表示將來打算進行或期待發生的動作或狀態。例如：
I shall graduate next year.

表示過去習慣性動作。
He always went to class last.
I used to do my homework in the library.（注意與be used to doing短語的區別）

在since 引導的狀語子句多用一般過去式.主句中一般用完成式
He has changed much since I saw him last.

過去式用wish表示否定語氣
I wish I could remember it.
I wish I had been there.

If I were you, I would stay at home.
If it hadn't been raining, I would have come to visit you.

但有幾種替代過去式的情況：
1）be going to +v在口語中廣泛使用，表示準備做或將發生的事情。例如：
I’m going to buy a house when we’ve saved enough money.

2）be to +v表示計畫安排要做的事，具有“必要”的強制性意義。例如：
I am to play tennis this afternoon.

3）be about to +v表示即將發生的事情。例如：
He was about to start.

4）be due to +v表示預先確定了的事， 必定發生的事。例如：
The train is due to depart in ten minutes.

5）be on the point/verge of + Ving 強調即將發生的某種事態。例如：
The baby was on the point of crying when her mother finally came home.

6) 有些動詞用現在進行式,表示在最近按計劃或安排要進行的動作,多和表示未來時間的狀語連用

We are leaving on Friday.

現在進行式
表示現在正在進行的動作，常與now，right now，at the moment，for the time being，for the present等連用。例如：
Don’t disturb her. She is reading a newspaper now.

表示現階段經常發生的動作， 常與always，continually，forever，constantly等連用。例如：
My father is forever criticizing me.

表示根據計畫或安排在最近要進行的事情。具有這種語法功能的動詞僅限於過渡性動詞。即表示從一個狀態或位置轉移到另一個狀態或位置上去的動詞。常用的有：go，come，leave，start，arrive，return等。例如：
They are leaving for Hong Kong next month.

有些動詞不能用進行式，這是一類表示“感覺，感情，存在，從屬”等的動詞。如：see，hear，smell，taste，feel，notice，look，appear，（表示感覺的詞）；hate，love，fear，like，want，wish，prefer，refuse，forgive（表示感情的動詞）；be，exist，remain，stay，obtain（表示存在狀態的動詞）；have，possess，own，contain，belong，consist of，form（表示佔有與從屬的動詞）；understand，know，believe，doubt，forget，remember（表示思考理解的動詞）。但是如果它們詞義改變，便也可用進行式態。例如：
Tom looks pale. What’s wrong with him?（look 在此為聯繫動詞，意為“顯得，看上去
Tom is looking for his books.

（look 在此為實義動詞，意為“尋找”）

過去進行式
過去進行式表示一個過去的動作發生時或發生後，另一個過去的動作正在進行，或表示過去反復的習慣，常與always，continually，constantly等動詞連用。例如
We were discussing the matter when the headmaster entered.
Whenever I visited him, he was always writing at the desk.

未來進行式
未來進行式主要表示將來某一時刻正在進行的動作，或表示要在將來某一時刻開始，並繼續下去的動作。
This time next day they will be sitting in the cinema.

表示禮貌的詢問、請求等。例如：
What will you be doing at six tomorrow evening?

現在完成式
現在完成式用來表示對目前狀況仍有影響的，剛剛完成的動作（常與yet，already，just連用），或者過去某一時刻發生的，持續到現在的情況（常與for，since連用）。例如：
I have just finished my homework.
John and Mary have know each other since 1990.
Mary has been ill for three days.
I have seen an elephant several times.
He has lived in the village for ten years.
She has gone to Pusan with her son. = She went to Pusan with her son and she is not here now.

常與現在完成式連用的時間狀語有：since, for, during, over等引導出的短語；副詞already, yet, just, ever, now, before, often, lately, recently等；狀語片語this week (morning, month, year), so far, up to now, many times, up to the present等。例如：
I haven’t been there for five years.
So far, she hasn’t enjoyed the summer vacation.
There have been a lot of changes since 1978.

如果主句的動詞是一般現在式，子句的動詞通常用現在完成式；如果主句動詞是過去式，子句動詞通常用過去完成式。例如：
This is one of the rarest questions that have ever been raised at such a meeting.
There was a knock at the door. That was the second time someone had interrupted me that evening.

過去完成式
表示過去某時間前已經發生的動作或情況，這個過去的時間可以用by，before等介詞短語或一個時間狀語子句來表示；或者表示一個動作在另一個過去動作之前已經完成。例如：
We had just had our breakfast when Tom came in.
By the end of last year they had turned out 5, 000 bicycles.

動詞expect, hope, mean, intend, plan, suppose, wish, want, desire等用過去完成式，表示過去的希望、預期、意圖或願望等沒有實現。例如：
I had meant to take a good holiday this year, but I wasn’t able to get away.

另外兩種表示“過去想做而未做的事”的表達方式是：
1）was / were + to have done sth, 例如：
We were to have come yesterday, but we couldn’t.

2）intended (expected, hope, meant, planned, supposed, wished, wanted, desired) + to have done sth, 例如：
I meant to have told you about it, but I forgot to do so.

過去完成式常用於以下固定句型：

1）hardly, scarcely, barely + 過去完成式+ when + 過去式。例如：
Hardly had I got on the bus when it started to move.

2）no sooner +過去完成式+ than +過去式。例如：
No sooner had I gone out than he came to see me.

3）by (the end of ) +過去式間，主句中謂語動詞用過去完成式。例如：

The experiment had been finished by 4 o’clock yesterday afternoon.

未來完成式
未來完成式表示在未來某一時刻將完成或在另一個未來的動作發生之前已經完成的動作；也可以用來表示一種猜測。常與未來完成式連用的時間狀語有：by (the time / the end of ) + 表示未來時間的短語和句子；before (the end of ) + 表示未時間的詞語或句子；when, after等加上表示未來動作的句子等。例如：
I will have finish this work by five o’clock.
He will have bought a house before he is forty.
I shall have read it three times if I read it again.
By this time tomorrow you will have arrived in Shanghai.
I shall have finished this composition before 9 o’clock.
When we get on the railway station, the train will probably have left.

現在完成進行式
現在完成進行式表示過去某一時刻之前開始的動作或狀態一直延續到過去某一時刻。例如：
I have been looking for my lost book for three days, but I still haven’t found it.

有少數動詞如work, study, live, teach 等, 用現在完成式和現在完成進行式意思相差無幾.
How long have you studied here?
How long have you been studying here?

但就大多數動詞而言,在不用表示一段時間地狀語的情況下,現在完成式表示動作的完成,而現在完成進行式表示動作的繼續.
They have widened the road.
They have been widening the road.

過去完成進行式
過去完成進行式表示過去某一時刻之前開始的動作或狀態一直延續到過去某一時刻。例如：
It had been raining cats and dogs for over a week and the downpour had caused landslides in many places.

未來完成進行式
未來完成進行式表示在未來某一時刻之前開始的一個動作或狀態一直延續到未來某一時刻。例如：
By the time you arrive tonight, she will have been typing for hours.

過去進行式
I was talking on the phone when she left.
It was out of army 3 months ago.
I have been out of army 3 months. (過去完成式)

I put the bottle on the table.(現在式)
The bottle was put on the table by me.(過去式)
The bottle has been put on the table by me.(過去完成式)


過去式:
表示較早的動作
I know that I made the right choice.
表示另一完成的動作
I wanted to go home because I missed my parents.
未來式:
表示同時發生的動作/現在式
I will be so happy if they fix my car today.
表示較早的動作/過去式
You will surely pass this exam if you studied hard.

現在完成式:表示從過去某一時間點持續到現在的一段時間
They believe that they have elected the right candidate.
未來式:表示即將來臨的動作
The President says that he will veto the bill.


過去完成式:
表示較早的動作
She knew she had made the right choice.
現在式敘述普遍的事實和真理
The Deists believed that the universe is like a giant clock.
現在完成式或過去完成式無論何種目的
She has grown 30cm since she turned nine.
The crowd had turned nasty before the sheriff returned.


現在完成式:表示比獨立子句的動作還要早的未來動作
The college will probably close its doors next summer if enrollments have not increased.
未來完成式:無論何種目的/現在式或現在完成式
Most students will have taken sixty credits by the time they graduate.
Most students will have taken sixty credits by the time they have graduated.