(一)情態(tài)動(dòng)詞

1、情態(tài)動(dòng)詞在句中沒(méi)有人稱和數(shù)的變化。

7．　 在It is time that, I would rather that句式中從句謂語(yǔ)動(dòng)詞用過(guò)去式。例如：

It is time we went to bed.

I would rather he came next week.

第二節(jié) 實(shí)戰(zhàn)演練

6．　 在有些句型中如：It is important (necessary、natural、strange等) + that從句中的謂語(yǔ)動(dòng)詞用should + 動(dòng)詞原形，should可以省略。例如：

It is necessary that the doctor (should) be sent there at once.

5．　 在有些動(dòng)詞如：suggest、insist、order等動(dòng)詞后，從句謂語(yǔ)動(dòng)詞用“should + 動(dòng)詞原形”，should可以省略。例如：

He suggested that we (should) discuss the problem right now.

4．　 動(dòng)詞wish后的賓語(yǔ)從句中，謂語(yǔ)動(dòng)詞可用過(guò)去式、過(guò)去完成式或would、might加原形。

例如：I wish I were as strong as you.

He wished I would stay with us.

She wished I had attended the meeting yesterday.

3．　 表示與將來(lái)事實(shí)相反的謂語(yǔ)形式。

例如：If they came tomorrow, we would told them about it. (In fact, they won’t come tomorrow。)

2．　 表示與過(guò)去事實(shí)相反的謂語(yǔ)形式。

例如：If I had left a little earlier, I would have caught the early bus. (In fact, I didn’t catch the bus.)

虛擬語(yǔ)氣表示說(shuō)話人的意愿、假設(shè)、猜測(cè)或建議。虛擬語(yǔ)氣不表示客觀存在的事實(shí)，謂語(yǔ)動(dòng)詞用特殊的形式表示虛擬語(yǔ)氣。

1．　 表示與現(xiàn)在事實(shí)相反時(shí)的謂語(yǔ)形式。

例如：If Tom were hungry, he would eat the bread. (In fact, Tom isn’t hungry.)

4. must與have to比較

must側(cè)重于個(gè)人意志和主觀上的必要，have to側(cè)重于客觀上的必要。如果用于過(guò)去時(shí)態(tài)或?qū)��?lái)時(shí)態(tài)時(shí)，則要用have to的相應(yīng)時(shí)態(tài)來(lái)代替must。但must可用于間接引語(yǔ)中表示過(guò)去的必要或義務(wù)。

My brother was very ill，so I had to call for the doctor in the middle of the night.

我弟弟病得很厲害，我只得半夜里把醫(yī)生請(qǐng)來(lái)。(一般過(guò)去時(shí))

I haven't got any money with me，so I'll have to borrow some from my friend.

我身上沒(méi)有錢，只好向朋友借點(diǎn)了。(一般將來(lái)時(shí))

He said that they must work hard.他說(shuō)他們必須努力工作。

3. have to的疑問(wèn)句

句型：Do(Does, Did, Will)+主語(yǔ)+have to +動(dòng)詞原形？

Do you have to study maths now？

你現(xiàn)在必須學(xué)數(shù)字嗎？

Yes，I do.是的，必須學(xué)。

No，I don't(have to)。不，不必學(xué)。

Did he have to ask the question？

他非要問(wèn)那個(gè)問(wèn)題嗎？

Yes，he did.是的。

No，he didn't(have to).不。