定義：表示假定、想像、願望等非事實的句子。如果表示事實，則使用「單純條件句」。通則：表示非事實假設時，要將敘述時態往前「平移」一個時態。例如「現在非事實」則使用過去式，「過去非事實」使用過去完成式。
Ⅰ. 與現在事實相反之假設語氣：
【_______________________________________】
1. If I had enough money, I would buy a new house.
2. If I were you, I wouldn’t lend him money.
3. If Bill were here, he would kill you.
4. If the weather were nice, I would go shopping.
5. If I knew how to swim, I would go to the beach with you.
6. ________________________________________________如果我有空，我會陪你去看電影。
7. ________________________________________________如果我是鳥，我就會飛了。
8. ________________________________________________如果蓋瑞有一台電腦，他一定很快樂。
9. ________________________________________________如果我看到瑪莉，我會告訴她事實。
Ⅱ. 與過去事實相反之假設語氣：
【_______________________________________】
1. If I had had enough money, I would have bought a car.
2. If you had not helped me, I would have failed.
3. If John had obeyed the doctor’s directions, he wouldn’t have died.
4. If the weather had been nice, we might have climbed Mt. Ali.
5. ________________________________________________如果你那時用功，你早就通過考試了。
6. ________________________________________________如果安妮當時能夠跑快一點，她就不會錯過火車了。
7. ________________________________________________如果他當時接受母親的忠告，他現在會幸福一些。
Ⅲ. 與未來事實相反之假設語氣：
【_______________________________________】
1. If Tim should pass the test, his parents would be very happy.
2. If you were to be reborn, what would you do?
3. If the sun were to rise in the west, I would buy you dinner.
4. ________________________________________________萬一瑪莉失敗了，她會很傷心。
5. ________________________________________________如果明天你來我家，我就告訴你答案。(但我知道你明天不可能來我家)
Ⅳ. 可能發生之假設語氣：
【_______________________________________】
1. If you need some money, I can lend you some.
2. If it is fine tomorrow, I will go camping.
3. ________________________________________________如果消息正確，約翰會很高興。
Ⅴ. 假設語氣之省略:
1. If I were young, I would climb Mt. Jade. = Were I young, I would climb Mt. Jade.
2. If you should meet Bill, tell him to call Mary. = Should you meet Bill, tell him to call Mary.
3. If Miss Wang could do it for me, I would be very grateful. = Could Miss Wang do it for me, I would be very grateful.
4. If I knew the secret, I would tell you about it. = Did I know the secret, I would tell you about it.
Ⅵ. BUT FOR (若非、要不是)
1. But for your help, I would have failed. (相反於過去)
2. But for his poverty, he might go abroad. (相反於現在)
Ⅶ. AS IF / AS THOUGH (好像、似乎)
1. He looks as if he were ill.
2. Tom looks as if he had been ill.
3. The old man talks and acts as if he might not live long.
4. He talks as if he were a teacher.
5. You look as if you had seen a ghost.
Ⅷ. WISH (但願；要是………就好了)
A. 與現在事實相反【_______________________________________】
1. I wish I knew how to swim.
2. John wishes he could speak English.
3. ________________________________________________要是我有一部跑車就好了。
B. 與過去事實相反【_______________________________________】
1. I wish (that) I had studied for the test.
2. Jack wishes he had visited his uncle.
3. I wish I had had enough money.
4. We wish the weather had been nice.
5. ________________________________________________但願我曾去過台南。
<補充>
1. It is high time that you spent more time on your schoolwork.
2. It is time that the government took urgent measures to crack down on crime.
1. I suggest that she go to see a doctor as soon as possible.
2. The landlord insisted that he pay the rent immediately.
1. 假如沒有電視，人們也許在閱讀上花更多的時間。
_________________________________________________________
2. 假如我是你，我當然會接受他提供的事情。
_________________________________________________________
3. 萬一他落選，我確信他會再接再厲。
_________________________________________________________
4. 假如我現在能打工，我就不需要向父母親要零用錢。
_________________________________________________________
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