浅谈as引导的非限制性定语从句的形式特点

浅谈as引导的非限制性定语从句的形式特点 1. _is known to everyone, the moon travels round the earth once every moth. A. ItB. AsC. ThatD. What 正确答案应选B项。这是一道由as引导的非限制性定语从句的语法题。在句中，as为关系代词，在从句中作主语，代表整个主句the moon travels round the earth once every month。在形式上，从句与主句用逗号隔开。此句译为：正如人们所知的那样，月球每个月绕地球一周。在实际做题时，许多学生错误地选择了答案A项，原因在于他们没有搞清楚此类句型的特点。 2. _ is known to everyone that the moon travels round the earth once every month. A. ItB. AsC. ThatD. What 正确答案应选A项。初看起来，此题与上题相似，但实际上有着较大的差别。此句属于名词性从句中的主语从句。在句中，It为形式主语，that引导主语从句the moon travels round the earth once every month。形式上没有逗号隔开。此句译为：月球每个月绕地球一周是人们所共知的。 为了让大家能更好地理解和掌握as引导的非限制性定语从句，现举例予以说明： （1）The compass, as is well-known to all, was invited in ancient China. 众所周知，指南针是中国古时发明的。 （2）He seems a farmer, as in actual fact he is. 他看上去像个农民，事实上他就是农民。 （3）As we know, Taiwan is a part of China.正如我们所知道的，台湾是中国的一部分。（as在从句中作know的宾语，代表主句Taiwan is a part of China） 从以上句子可以看出，as引导的非限制性定语从句具有以下特点： （1）其先行词可为整个主句，也可为某一个名词。 （2）as在从句中可以作主语、表语或宾语。用作主语时，谓语动词用单数形式。 （3）其从句可以放在主句的前面或后面，也可以放在整个句子中间。也就是说从句可以位于句首、句中或句末，但习惯用逗号隔开。 （4）as仍有“正如那样；像一样；由而知”等作连词时的词义。 （5）在句法上，as常被用作一些实义动词的表语及其被动语态的主语，如see, know, say, report, imagine, show, remember, point out等动词。常见的词组有： as is well known to all / as we all know 众所周知 as has been said before 如上所说 as you expected 如你所料 as has been already reported 据报道可知 as she imagined 如她所想像的那样 as it showed 正如所反映的那样 as anybody can see 正如人们所看到的那样 as除了能引导非限制性定语从句外，还能引导限制性定语从句。常与the same或such连用，构成：the sameas, suchas。as引导限制性定语从句时，在从句中同样可以作主语、表语或宾语。如： （1）Such Chinese as is spoken in Shanxi is not Putonghua. We call it the Shanxi dialect.在陕西说的汉语不是普通话，我们称为陕西方言。（as在从句中作主语） （2）I have the same book as you have. 我的书和你的一样。（as在从句中作have的宾语） （3）He is not such a clever person as she is. 他不像她那样聪明。（as在从句中作is的表语）【就远原则】谓语动词与前面主语一致 代表词汇：as well as；（together/along/combined）with；rather than；except；besides；but；including；in addition to；apart from；like ；as much as ；no less than例如：Nobody but two students is in the classroom.除了这两个学生,没有人在教室 Everybody except you is down on me.除了你,大家都看不起我.A woman with two children has come.一位妇女带着两个孩子已经来了.John, rather than his roommates, is to blame.约翰,而不是他的室友,应该受到责备.Jim , together with his classmates ,has seen the film. 吉姆和他的同学都看过这部电影.My father, no less than I, is a base-ball fan.我的父亲不亚于我也是个棒球迷.The son, as well as his parents, wants to go there.不但儿子想去那儿,而且他的父母也想去.The teacher, as well as the students, is interested in the activity.老师也和同学们一样对这项活动有兴趣【就近原则】由下列词语连接的并列主语：there be+句型; or ; either or；nor; neithernor；whetheror；notbut; not onlybut also ; 等. What he does or what he says does not concern me.他的行为或言谈都与我无关. Neither you nor I am wrong .你和我都没错. Not you but your father is to blame.不是你,而是你的父亲该受责备. Not only you but(also) he is wrong.不仅你错了,他也错了.which与as引导非限制性定语从句的异同一、相同点两者引导非限制性定语从句时，可指代主句中的部分或整个句子的内容，在从句中做主语，宾语或表语，位于主句之后有时可互换。The meeting was put off, as /which was exactly what we wanted.He was a doctor, as/which I knew from his manner.二、不同点1. as可以放在主句前后，也可插入主句之中；而which引导的非限制性从句只能位于主句之后。As is known to all, fish cant live without water.Air, as we know, is gas.2.在非限制性从句中，which后的be动词不可省；as而后的be动词可以省略。She told me she won the match, which was a lie.The material is elastic, as (was) shown in the figure.3. which在非限制性定语从句做主语时可用各类动词做谓语；而as做主语时，谓语常用系动词，如be, seem, become等，一般不用其他行为动词。He saw the girl, which delighted him.He didnt say anything at the meeting , as/which seemed very strange.4. as常用“正如”含义，常用的结构有as we know（众所周知）；as often happens（正如常发生的那样）；as is often the case（情况常常如此）; as we all can see（正如我们看到的）; be announced/expected/known/imagined/mentioned/said/shown/reported等。这些结构常放句首，偶尔也可以放句中或句末。As is known to all, China is a developing country.Kate was late for school, as often happened.5. 在非限制性定语从句中which指代主句中某一个单词时，as不可以。My brother enjoyed playing basketball, which he really plays well.Beijing, which he was born in, is our capital.6. “介词+关系代词（介宾代物）”中关系代词只能用which。The Travel Agency, with which our company has been dealing for several years, has opened for new branches. Air is a mixture of gases, of which oxygen forms 21 percent.7. 从句中的谓语动词是