would rather that somebody did…"宁愿……;更愿意……"(表示现在或将来的愿望)
would rather that somebody had done…"宁愿……;更愿意……"(表示过去的愿望)
I'd rather you posted the letter right now. 我想让你现在去寄信。
I'd rather you were not a celebrated actor. In that case, we could spend more time together.
I'd rather that I hadn't seen her yesterday. 我情愿昨天没有看到她。
as if/though+主语+did/had done…好像……(表示现在或将来的情况用过去时;表示过去的情况用过去完成时)[参考句型4]
Our head teacher treats us as if we were her own children, so all the students in our class think highly of her.
Alan talked about Rome as if he had been there. Alan谈起罗马来就好像他去过那里似的。
How I wish we students had more free time to relax ourselves! 我们学生多么希望有更多的自由时间放松自己!
I failed in the maths exam. How I wish I hadn't wasted so much time playing!
What a pity you can't go to the party. How I wish I could dance with you at the party!
It's high/about time that somebody did (should do) (should通常不省略) …早就该……
It's time that you went to school.= It's time that you should go to school.
It's high time that we did something to improve our environment. 该是我们为环保做些事情的时候了。
I think it's high time that she made up her mind. 我想她该拿定主意了。
could have done "本来可以……"(表示过去没有实现的可能)。
might have done "本来可能……;本来应该或可以做某事"(实际没有发生;含有轻微的责备语气。）
should/ought to have done "本来该做某事"(而实际未做)
should not/ought not to have done "本来不该做"(实际却做过了，含有责备语气)
needn't have done "本来不必做"(但是已经做过了)
would rather have done "当时宁愿做了某事"(实际没有做过);否定式would rather not have done表达相反意思，两者都有表示"后悔"之意。
as, though, although引导的让步状语从句。
1. Although/Though I'm young, I already know what career I want to follow.
→Young as/though I am, I already know what career I want to follow.
2. Although/Though I respect him very much, I cannot agree with his idea.
→Much as/though I respect him, I cannot agree with his idea. 虽然我很尊重他，但是我不同意他的观点。
3. Although/Though he is a child, he knows a lot of Chinese characters.
→Child(省略冠词)as/though he is, he knows a lot of Chinese characters. 他虽然还是个孩子，却认识了许多汉字。
4. Although he tried, he couldn't solve the problem.
→Try as he might, he couldn't solve the problem. 尽管他努力了，但是他没有解决问题。
5. Although it is raining, I'm going out for a walk.
→Raining as it is, I'm going out for a walk. 天虽然在下雨，我还是要出去散步。
6. Strange as it may seem, nobody was injured in the accident. 这次意外虽然显得不可思议，却没有人受伤。
7. Much as I would like to help, I have a lot to do. 虽然我很想帮助你，但是我有很多事要做。
8. Object as you may, I will go. 纵使你反对，我也要去。
The roof fell before he had time to dash into the room to save his baby.
He ran off before I could stop him. 我还没有来得及阻止，他已经跑了。
To my great disappointment, my favorite singer left the concert before I could have a word with her.
They walked about fifty miles to the west before they saw a village.
The workers worked day and night about three days before everything returned to normal.
He almost knocked me down before he knew it.
We had walked a long way before we found some water.
Five years went by before I knew it. 不知不觉，五年过去了。
It was + 时间段+before…."过了多久才(怎么样)……"
It was not long before…."不久，就……"
It will (not) be +时间段+before…"要过多久(不久)……才……"(before从句谓语动词要用一般时态)
It was not long before he sensed the danger of the position.不久他就意识到他处境的危险。
It was five days before he came back. 五天后他才回来。
It will be half a year before you graduate from the school. 再过半年你才能毕业。
It will not be long before they understand each other. 他们大概不久就会互相了解。
in case of…(+n.) "以防;万一";
in case that…"以防，万一……"(谓语动词用一般现在时态或should+动词原形)
In case of fire, what should we do?
Please remind me about it in case I forget/should forget. 万一我忘了，请提醒我。
In case (that) John comes/should come, please tell him to wait.
Please take your umbrella in case (that it rains/should rain).带上雨伞，以防下雨。