If从句中一般不用would:
I’d be very frightened if somebody pointed a gun at me.(而非if somebody would point)
If I didn’t go to their party, they’d be offended(而非if I wouldn’t go)
If …….would可以表示用来请求某人做某事:
I would be grateful if you would send me your brochure as soon as possible.
“Shall I close the door?” “yes, please, If you would.”
Would(‘d) / wouldn’t用于句子的主句(不是if从句)
If you took more exercise, you’d (=you would) probably feel healthier.
Would you mind if I used your phone?
I’m not tired enough to go to bed yet. I wouldn’t sleep.
另外,if引导的条件句也能引起倒装,如果要是在作文里用到,也是一个加分点:
先看正常语序.
It would be a serious setback, if the talks were to fail.
If you should need more information, please telephone our main office.
If Alex had asked, I would have been able to help.