衛(wèi)生類職稱英語(yǔ)考試語(yǔ)法：

情態(tài)動(dòng)詞表示說話人的語(yǔ)氣或情態(tài)，如請(qǐng)求、命令、愿望、能力以及可能性等，它有一定的詞義，沒有人稱和數(shù)的變化。英語(yǔ)的情態(tài)動(dòng)詞有：

can,could

may,might

must

ought to

shall,should

will,would

dare,dared

need

1.can,could

（1）能，能夠、會(huì)、可以

Energy can be changed from one form into another.

We can buy a car by installments.

（2）許可

You can （= may） go home now.

（3）表懷疑，難以置信

He couldn't （can't） be her father; he is too young.

（4）could + have + p.p.

He could have passed the exam.

（5）be able to是can的同義結(jié)構(gòu)

Thus,we shall be able to determine the amount of alcohol burned.

They have not been able to come.

2.may ,might

（1）允許、請(qǐng)求

Excuse me,may I have a glass of water?

（2）可能，或許；用might語(yǔ)氣更加不肯定

These ideas may seem strange to you.

He might get lost.

（3）may （might） + have + p.p.表對(duì)過去的推測(cè)

She may （might） have missed the bus.

（4）表祝愿

May all your dreams come true.

May it be so.

（5）be allowed to是may的同義結(jié)構(gòu)

You will be allowed to use this computer.

3.must

（1）必須，應(yīng)該

The auditor must conduct sufficient verification.

（2）must not意為“不應(yīng)該”，“不許”

We must not be afraid of difficulties.

— Must I return the book?

—Yes,you must./ No,you needn't.

（3）must + have + pp 表對(duì)過去的推測(cè)

I can't find my umbrella.Someone must have taken it.

（4）must + be + -ing 一定在…

They must be talking about us now.

（5）have to是must的同義結(jié)構(gòu)

We will have to change our plan.

4.ought to

（1）應(yīng)該

We ought to make the most of our time.

（2）ought to + have + p.p.表過去沒完成的事

She ought to have come to see me two days ago,but she forgot.

（3）表推測(cè)

This arrangement ought to please them.

5.Shall

（1）征求意見

— Shall I close the door?

— Yes,please./ No,please don't.

6.Should

（1）應(yīng)該

A formal written appraisal should be prepared annually.

（2）推測(cè)

They should be home by now.

（3）should + have + p.p.表過去應(yīng)做但沒做的事，含有責(zé)備的意思。

This conclusion should have been double-checked.

（4）表憤怒，不滿，失望

I am very sorry that he should be so careless.

（5）用于讓步從句中

He run away lest he should be seen.

7.will

（1）請(qǐng)求

Will you lend me your dictionary?

（2）自然規(guī)律，習(xí)慣動(dòng)作

Fish will die out of water.

Water will boil at 100 degrees centigrade.

8.would

（1）委婉請(qǐng)求或命令

Would you take a seat?

（2）表過去習(xí)慣性動(dòng)作

He would sit there for hours,doing nothing.

9.dare ,dared

（1）敢

How dare you speak to me like that?

No one dared speak of it.

（2）有時(shí)后面跟不定式，用作行為動(dòng)詞

He dares to think,to speak,and to act.

10.need

（1）“需要”，用于否定句和疑問句中

— Need I show you my passport?

— Yes,you must./ No,you needn't.

We didn't need to call the doctor.

（2）needn't + have + p.p.表本不必做

She needn't have watered the flowers.