If he were to come here,he would tell us about it.
如果他要来的话,他会通知我们一声.
If you should go to Qing Hua University,you would make full use of your time.
如果你想上清华大学,你就要充分利用你的时间.
If I had time tomorrow,I would help mother with the housework .
如果明天我有时间,我会帮妈妈干家务活.