1、GrammarThe number of smokers,_ is reported,has dropped by 17 percent in just one yearA.itB.whichC.whatD.as as与which 引导非限制性定语从句的区别As is known to all,China is a developing country.Mark Twain,as we know,is a famous American writer.He doesnt like the job,as you can see.The roads were flooded,which made
2、our journey more difficult.As is known to all,China is a developing country.Mark Twain,as we know,is a famous American writer.He doesnt like the job,as you can see.The roads were flooded,which made our journey more difficult.一一位置不一样位置不一样as可放在句首可放在句首句中或者句尾；句中或者句尾；As is known to all,China is a develop
3、ing country.Mark Twain,as we know,is a famous American writer.He doesnt like the job,as you can see.which只能放在主句后只能放在主句后The roads were flooded,which made our journey more difficult.He cannot pay off his debt,as is the case.Our team won the match,as we expected.He broke his promise,which made me angry
4、.He cannot pay off his debt,as is the case.Our team won the match,as we expected.He broke his promise,which made me angry.二二.意义不一样意义不一样as常译为常译为“正如，如同正如，如同”，主从复合句常为，主从复合句常为顺承关系；顺承关系；He cannot pay off his debt,as is the case.Our team won the match,as we expected.which常译为常译为“这这”，主从句之间常为转折，主从句之间常为转折，因果关
5、系。因果关系。asas固定词组搭配固定词组搭配 as we all know=as is known to all as is the case as is said/reported/expected as often happensThe number of smokers,_ is reported,has dropped by 17 percent in just one yearA.itB.whichC.whatD.asDHe won the first place in the match,of which we were proud.The weather turned out
6、to be terrible,about which we were disappointed.He won the first place in the match,of which we were proud.The weather turned out to be terrible,about which we were disappointed.三介词+which结构在介词后代替整个主句时，只能用which.The driver said he hadnt drunk,which the traffic policeman didnt believe.The driver said h
7、e hadnt drunk,which the traffic policeman didnt believe._ The policeman ordered the drunk driver to leave the car,which he did.五四当关系代词代替主句中的宾语从句时，一般只用which,不用as。1,as引导 非限制性定语从句时，可放句首，句中，句末。which 引导非限制性定语从句时，从通常在主句之后.2,as常译为“正如，如同”，主从复合句常为顺承关系，which常译为“这”，主从句之间常为转折，因果关系。3，as常用于一些固定结构。4，which常用于介词+whi
8、ch结构中。5,当关系代词代替主句中的宾语从句或复合句结构时，一般只用which，而不能用as_1，改错。，改错。It is known to all,the earth moves around the sun.As通过分析句子结构可知，本句是非限制行定语从句。通过分析句子结构可知，本句是非限制行定语从句。所缺词一方面代替主句的意思，另一方面连接从句，所缺词一方面代替主句的意思，另一方面连接从句，意为意为“正如正如”，故需要将，故需要将ItIt改为改为AsAs。另外，。另外，itit属于属于代词，可以作形式主语，如将题干中的逗号改为代词，可以作形式主语，如将题干中的逗号改为thatthat也可以。也可以。追踪练习追踪练习追踪练习追踪练习2.单选。Tom did not pass the final exam this time,_is often the case.A.it B.which C.as D.whoC解析，解析，as引导非限制性定语从句时，引导非限制性定语从句时，常用常用”As is often the case”等结构中，等结构中，故答案为故答案为C。追踪练习追踪练习谢谢指导!
