句型17.
由which引导的非限定性的定语从句。如：
He is a professor, which I have been looking forward to becoming. 他是个教授，那是我一直盼望的职业。（因为先行词professor是表示职业的名词，因此引导词用which，而不用who。）
句型18.
由where, when引导的定语从句（其中包括限定性的或非限定性的。）如：
This is the house where I used to come.
请比较：This is the house which / that I used tocome to.
This is the day when I joined the Party.
请比较：This is the day which / that I joined the Party on. （说明：关于that与which之间的区别，请看关系代词that和which的区别。）
句型19.
No matter what / which / who / where / when / whose＋从句，＋主句.(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。）
句型20.
When / So long as / As long as / Once +从句，＋主句。（从句也可以放在主句之后。）如：
As long as you give me any money, I will let you go.只要你给我一些钱，我就让你走。
Once you have begun to learn English, you should learn it well. 一旦你开始学习英语，你应该把它学好。
句型21.
主句＋on condition that+从句.如：
I will go with you on condition that you give me a sum of money.我和你一起去的条件是你给我一些钱。
句型22.
主句＋unless+从句.(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。)如：
I will go there tomorrow unless it rains.我明天去那儿除非下雨。
句型23.
祈使句，＋and/ and then+主句。（注意：祈使句也可用一个名词短语。）如：
Use your head, and you will find a good idea.动脑筋想一想，你就会想出一个好主意。
Another word, and I will beat you.你再说一句，我就揍你。
句型24.
If +necessary / impossible/ important等，＋主句.(注意：if与形容词之间的it is被省略。)如：
If necessary, I will do it. 如果有必要的话，我来做此事。作者: leenyao 时间: 2010-11-18 15:27
thanks for sharing作者: xiaomeixin 时间: 2010-11-18 15:33
Thanks for sharing.It's useful.作者: evaxiaofan 时间: 2010-11-19 10:05
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