學會了現在假設語氣的概念，再學 過去假設 語氣就容易多了！
什麼是過去假設？過去假設的基本概念就是表示「與過去事實相反的事情」，基本動詞結構是had pp，遇到助動詞時，使用過去式助動詞再加have pp。
I. 基本句型：If + S + had pp, S + would/could/might + have pp
- 過去假設的基本句型為 If + S + had pp, S + would/could/might + have pp
(had pp)。。。。(V-ed)。。。。(V/V-es)。。。。。。(will V)
在if子句中，過去假設使用的動詞為過去完成式had pp，主要子句中常會使用助動詞，加上後had pp變成助動詞 + have pp。
If Frank had been more careful, he could have avoided such mistakes.
If Diana had got up earlier this morning, she might have caught the train.
Professor Wang would have asked the student to resubmit his report if he had failed the final exam.
If David had won the lottery, he could have paid for his family’s trip to Canada.
II. 否定句型：If + S + had not pp, S + would/could/might + (not) + have pp
- 過去假設的否定，只要將had pp改成否定hadn’t pp即可。
- 主要子句的否定是在助動詞後加上not，例如wouldn’t have pp。
- 否定的被動：If子句用had not been pp，主要子句用would not have been pp。
If the chairman of this club had not changed the rules, many members would not have left this club.
If the broken bridge had not been repaired in time, many people would have lost their lives.
If the glass had not been doppred to the ground, the child would not have been injured.
- If Henry had not offended his boss last month, he would not be jobless now.
- If Mrs. Chen had managed her business well last year, she would not be bankrupt now.
- If Olivia had dried her hair right after washing it, she _________.
(A) might catch a cold
(B) would have caught a cold
(C) might not have caught a cold
(D) could not catch a cold
- If the weather _______ nice last weekend, the baseball game ________.
(A) had been; might not have been canceled
(B) were; might have canceled
(C) had been; might cancel
(D) were; might not be canceled
- If the famous painting ________ last year, visitors to this museum ________ it now.
(A) is stolen; can see
(B) had not been stolen; could see
(C) was not stolen; could have seen
(D) were not stolen; could have seen
Being hit by lightning is a rare event. Over the course of an 80-year life span, the odds of being hit by lightning are 1 in 3,000, not to mention the probability of being struck seven different times. Roy Sullivan, a park ranger in the United States, was struck by lightning more recorded times than any other human being. Over his 36-year career, Sullivan was struck by lightning seven times—and survived each shock!Strikes one, two, and three were pure bad luck, he thought. But after strike four, Sullivan became fearful of death and took precautions during lightning strikes. Strike five occurred in 1973 when Sullivan was on patrol. A storm cloud “chased” him until he was struck. The same thing happened again in 1976. Sullivan, while surveying a campground, felt that a cloud was coming after him, and tried all he could to run— but it got him anyway. Finally, on 25 June 1977, a seventh and final bolt struck Sullivan as he was fishing in a pond. “I don’t believe God is after me,” he theorized. “If he was, the first bolt __25__ enough. Best I can figure is that I have some chemical, some mineral, in my body that draws lightning. I just wish I knew.”25. (A) was (B) had been (C) would be (D) would have been