1.I would do it if I had the chance.如果有机会我会做那件事的。
这是一个表达与将来事实可能相反的虚拟语气句,if从句中用一般过去时,主句中用would do形式。又如:
I would go there if he invited me tomorrow.如果他明天邀请我,我便去那儿。
2.If only I could...!要是我能……该多好!
if only意“要是……就好”,常表达一种良好的愿望,句子谓语的形式主要有以下两种:
1)与现在或将来事实相反的愿望,谓语用一般过去时。如:
If I could only see him once!我只要见到他一次就好了!(与将来事实相反)
Oh,if he only knew how we miss him!但愿他知道我们多想念他!(与现在事实相反)
2)与过去事实相反,谓语用“had done(即过去完成时)”形式:
If only we had listened to their advice!我们要是听了他们的意见就好了!
3.I wish I could /had /were...但愿我能……
wish后的宾语从句谓语有三种形式:
1)与过去事实相反的愿望,宾语从句谓语动词用had done形式。如:
I wish I had paid more attention to my pronunciation when I was inmiddle school.我上中学时多注重些语音就好了。
2)与现在事实相反的愿望,宾语从句谓语动词用一般过去时形式。如:
I wish I remembered the address.我要是记得地址就好了。
3)与将来事实相反的愿望,宾语从句谓语动词为“would /coulddo”形式。如:
I wish I would /could fly to the moon some day.我要是有一天飞上月球就好了。
I wish he would try again.但愿他能再试一次。