if you work hard ,you will get good marks.
if i were you ,i would work harder at my lesson.
if you had followed my advice,you would be better now.
If I had known his telephone number, I would have called him.
If it should were to rain, we would call off the match.
If you had studied hard before, you would be a college student now.
If it should were to rain, we would call off the match.
If he had hurried ,he could have caught the train.
If I were to go abroad ,I would go to America.
If I had time, I would attend the meeting.
除了第一句其他都是虚拟语气
如果要知道意思你可以追问我