一、
　　1) 表示目的;它的否定式是so as not to do。
　　Tom kept quiet about the accident so as not to lose his job.
　　湯姆對事故保持沉默是為了不丟掉他的工作。
　　Go in quietly so as not to wake the baby.
　　輕點進(jìn)去，別驚醒了嬰兒。
　　2)　so kind as to ---勞駕
　　Would you be so kind as to tell me the time?
　　勞駕，現(xiàn)在幾點了。
　　二、
　　though, although
　　注意： 當(dāng)有though, although時，后面的從句不能有but，但是 though 和yet可連用
　　Although it‘s raining, they are still working in the field.
　　雖然在下雨，但他們?nèi)栽诘乩锔苫睢?br />　　He is very old, but he still works very hard.
　　雖然他很老，但仍然努力地工作。
　　Though the sore be healed, yet a scar may remain.
　　傷口雖愈合，但傷疤留下了。 (諺語)
　　典型例題
　　1) ___she is young, she knows quite a lot.
　　A. When　B. However　 C. Although　 D. Unless
　　答案：C。意為雖然她很年輕，卻知道許多。
　　2)　as, though 引導(dǎo)的倒裝句
　　as / though引導(dǎo)的讓步從句必須表語或狀語提前(形容詞、副詞、分詞、實義動詞提前)。
　　Child as /though he was, he knew what was the right thing to do.
　　= Though he was a small child, he knew what was the right thing to do.
　　注意： a.　句首名詞不能帶任何冠詞。
　　b.　句首是實義動詞，其他助動詞放在主語后。如果實義動詞有賓語和狀語，隨實義動詞一起放在主語之前。
　　Try hard as he will, he never seems able to do the work satisfactorily.
　　= Though he tries hard, he never seems…
　　雖然他盡了努力，但他的工作總做的不盡人意。
　　3)　ever if, even though.　即使
　　We‘ll make a trip even though the weather is bad.
　　4) whether…or-　 不管……都
　　Whether you believe it or not, it is true.
　　5)　"no matter +疑問詞" 或"疑問詞+后綴ever"
　　No matter what happened, he would not mind.
　　Whatever happened, he would not mind.
　　替換：no matter what = whatever
　　no matter who = whoever
　　no matter when = whenever
　　no matter where = wherever
　　no matter which = whichever
　　no matter how = however
　　注意：no matter 不能引導(dǎo)主語從句和賓語從句。
　　(錯)No matter what you say is of no use now.
　　(對)Whatever you say is of no use now.
　　你現(xiàn)在說什么也沒用了。(Whatever you say是主語從句)
　　(錯)Prisoners have to eat no matter what they‘re given,
　　(對)Prisoners have to eat whatever they‘re given.　囚犯們只能給什么吃什么。