让步状语从句
19. No matter what / which / who / where / when / whose+从句，+主句. 无论…
(注意从句中的时态一般情况下用一般现在时态。) 如：
No matter what you do, you must do it well.请比较：
Whatever you do, you must do it well. 无论你做什么，一定要做好。
No matter where you go, please let me know. 请比较：
Wherever you go, please let me know.你无论去哪儿，请通知我。
(说明：这两种句型形式不同，而意义完全相同。)
(注意：I will tell whoever would like to read it. 句中的whoever不能用whomever来代替。因为它即作动词tell的宾语，又作后面从句的主语。)
条件状语从句
20. So long as / As long as / Once +从句，+主句。(从句也可以放在主句之后。)
As long as you give me any money, I will let you go.只要你……
Once you have begun to learn English, you should learn it well.一旦……
21. 主句+on condition that+从句. 条件是……
I will go with you on condition that you give me a sum of money.
22. 主句+unless+从句.除非…… (注意：由于unless本身是否定词，所引导的从句的谓语动词用肯定而不用否定。)
I will go there tomorrow unless it rains.我明天去那儿除非下雨。
23. 祈使句，+and/ and then+主句。(注意：祈使句也可用一个名词短语。)
Use your head, and you will find a good idea.
Another word, and I will beat you. 你再说一句，我就揍你。
24. If +necessary / impossible/ important等，+主句.
(注意：if与形容词之间的it is被省略。)
If necessary, I will do it. 如果有必要的话，我来做此事。
