1．Tenses of Verbs动词时态

a．To show that the time of the action or state of being is now or that something is always true，use the present tense．

表明现在的动作或状态以及真理性的内容，通常用一般现在时。

I am eager to hear the results of the personnel recruitment．

Several items are out of stock．

Some prices in the ready product market rise frequently．

b．To show that the action occurred or that the state of being existed sometime before the present time，use past tense．

表明过去某时所发生的动作或事物所处的状态，通常用一般过去时。

He called me while you were away inspecting the factory．

I was in London for our global market summit last week．

Who took the message while the President was absent?

Some of the gifts were very expensive．

c．To show that the action will occur sometime in the future or that the state of being does not yet exist，use the future tense．

表明将来的动作或状态则用一般将来时。

You will be happy with the new fax machine．

They will receive two copies of bills of lading．

In very formal writing and speeches，use shall when the subject is I or we，and use will with any other subject．

在极其正规的场合，主语为第一人称一般用shall，其他人称用will。

We shall call the Wilsons next week，but they will not accept our offer．

To show determination or promise in very formal writing or speeches，use will when the subject is I or we and use shall when the subject is any other word．

但有时为表现说话人的誓言和决心，第一人称主语用will，其他人称则用shall。

I definitely will cancel my subscription．

The annual dues shall be $ 25．

d．To show that an action or a state of being began sometime in the past and may continue in the present，use the present perfect tense．

表明动作或状态发生在过去某个不确定时间，持续到现在并可能继续延续下去，通常用现在完成时。

We have shipped the order on scheduled time．

The L/C issued by the Commercial Bank has reached us．

Ms．Evens has interviewed many applicants for that position．

e．To show that something began and ended before the present time，use the past perfecttense．

表明发生在过去并且在过去完成的动作，通常用过去完成时。

All of us had been in San Antonio and had visited them before they moved into their new home．

Craig had prepared his report before he left for Dallas．

We had been interrupted ten times before 11 o'clock this morning．

f．To show that the action or state of being will begin and end at some particular time in the future，use the future perfect tense．

表明将来某时已经完成的动作或状态，通常用将来完成时。

On the first of July，I will have(or shall have)been with the same employer for five years．

Mr．Reed will have talked with all of the district managers by this time tomorrow．

Most of the apartments will have been rented by next week．

g．To show the action in progress or state of being in continuing existence at some particular time，use a present participle as a main verb．

表明任何时间正在进行的动作或状态，常用进行时，如现在进行时、过去进行时、现在完成进行时等。

I am being careful because my supervisor is watching me．

You are being invited to the seminar．

We have been conducting an informal survey．

She has been serving for Microsoft China for at least two years．

Some of us had been waiting for the inspection certificate for more than an hour．

Amy will have been working for the purchasing department for five years on April 10．