4.假設的條件不以條件從句, 而以其他方式如介詞短語、從句等表達出來, 這種句子稱為含蓄條件句

　　 　　a. What would you do with a million dollars?

　　 　　b. Without music, the world would be a dull place.

　　 c. We could have done better with more money.

　　 d. He would have given you more help, but he has been so busy.

3.主從句時間不一致時, 主從句謂語動詞的形式取決于要表示的具體時間

　　 　　a. You would speak English well if you had practised speaking it every day.

　　　　 b. If she hadn’t trained so hard, she wouldn’t be able to run so fast.

2.省略條件從句或主句, 省略部分的含義仍有所體現(xiàn). 省略主句時, 表示己不能實現(xiàn)的愿望

　　 　　a. You could have done it yourself (if you had wanted to).

　　 　　b. I wouldn’t smoke (if I were you).

　　 　　c. If my old friends were with me! (要是老朋友和我在一起該多好啊)

　　 　　d. If you could have seen the wonderful film!

1.條件從句省略if: 在書面語中, 如果條件從句中的謂語中有were, had, should等詞, 可將if省略, 而把were, had, should放在句首

　　 　　a. Were I you (=If I were you ), I would get up early very early.

　　 　　b. Had you arrived (=If you had arrived ) at the station ten minutes earlier yesterday, you could have caught the train.

3.表示與將來事實相反的情況時, if從句的謂語形式是: ①.完全動詞過去式 (be的過去式通常用were);　 ②.should +動詞原形;　 ③.were to do. 其中②, ③種情況都含有“出乎意料之外”之意; 主句的謂語的形式是: should / would / could / might +動詞原形

　　 　　a. If she should invite me tomorrow, I should go to the party.

　　 　　b. If it rained / should rain / were to rain tomorrow, our picnic would be put off.

　　 　　c. If I saw him tomorrow, I would pass your note to him.

　　 　　d. I might come back if I were to miss the train.

2.表示與過去事實相反的情況時, if從句的謂語用had done形式, 主句的謂語用should / would / could / might + have done的形式

　　 　　a. If she had invited me yesterday, I should have gone to the party.

　　 　　b. I would have checked my paper again if I had had more time at yesterday’s exam.

　　 　　c. If you had taken the teacher’s advice, you would not have failed in the exam.

1.表示與現(xiàn)在事實相反的情況時, if從句的謂語用動詞的過去式 (be動詞的過去式多用were, 而不用was), 主句的謂語用should / would / could / might +動詞原形 (should多用于第一人稱, would多用于二三人稱, could / might可用于所有人稱)

　　 　　a. If I had more time, I should study computer better.

　　 　　b. If he were not so busy, she would attend the meeting this afternoon.

　　 　　c. If they didn’t take exercises every day, they wouldn’t be so healthy.

　　 　　d. If you went to bed earlier, you would not be so sleepy in the morning.

　　 　　e. If she invited me, I should go to the party.

2.表示命令

　　 　　a. Everybody leave the room.

1.表示祝愿

　　 　　a. Long live our country.

　　 　　b. May you succeed.

　　 　　c. May you be happy all your life.

虛擬語氣的用法