定語從句之專題三：as引導定語從句。（系統講解內在原理）

(本文選自《魔方英語語法》第十一章第四節。已經登記版權，請勿用於商業用途。)

本文主要講as(代詞)引導定語從句和as(連詞)引導評述性狀語從句

分兩大類情況講解：

下邊詳細講解。

（一）as(代詞)引導限制性定語從句

1. 當先行詞是「such/the same+名詞」時，用as引導定語從句。即，such+n.+as(代詞)，the same+n.+as(代詞)。

例句（as指代such+n.，作主語/賓語/表語）

●We invited all such people as were likely to come.（as在從句中作主語。as=all such people，即，All such people were likely to come.）

●I have never heard such stories as he tells. 我從未聽說過他講的這類故事。（as在從句中作賓語。as=such stories，即，He tells such stories。）

●I』ve never seen such a fool as he is.（as在從句中作表語。as=such a fool，即，He is such a fool.）。

例句（as指代the same +n.，作主語/賓語/表語）

●Is this the same mosquito as bit you just now？（as作主語。The same mosquito (=as) bit you.）

●This is the same knife as I lost yesterday.（as作賓語。I lost the same knife (=as) yesterday.）

●She is just the same person as she used to be.（as作表語。She used to be the same person (=as).）

2.as與that的區別。

①such…as(代詞)引導定語從句，such…that(連詞)引導結果狀語從句。如，

●He is such a good boy as everyone likes.他是個人人都喜歡的好男孩。

（從句缺成分（缺賓語），因此as是代詞（作成分））

●He is such a good boy that everyone likes him.他是個好男孩，以至於人人都喜歡他。

（從句不缺成分，因此that是連詞（不作成分））

②the same…as(代詞)…，表示兩物相似；the same…that(代詞)…,表示兩物同一物。如，

●This is the same pen as I used yesterday.這是和我昨天用的一樣的鋼筆。

●This is the same pen that I used yesterday.這是我昨天用過的那支鋼筆。

注意：the same …，可以與代詞as/that連用，也可以與副詞when/where等連用。如，

●This is the same place where we had the party that day.（where作狀語）

（二）as(連詞)引導評述性狀語從句

評述性狀語從句，表示說話人的看法、態度、解釋或評論。as的意思是「正如/像」。

學習這塊內容，關鍵在於區別as與which。本書認為，as（連詞）引導評述性狀語從句，which（代詞）引導非限制性定語從句。所有的能換用/不能換用的情況，都可以用這點區別推導出來。下文中，1.講不能換用的情況；2.講能換用的情況。1和4是重點內容，2和3僅供了解。

1. as (連詞)引導評述性狀語從句，which (代詞)引導非限制定語從句。

（1）引導詞詞性不同。as是連詞，which是代詞。由此可以推導出：

（2）從句類型不同。as引導的是狀語從句，which引導的是定語從句。由此可以推導出：

2. as與which可以換用的三種情況，純屬巧合。

為何說純屬巧合呢？因為，as引導的是狀語從句，它可以省略無意義的it（作主/賓語時）或承前省略（作表語時）。在省略掉這些詞之後，湊巧可以把as換作which。

（1）which在「主系表」中作主語時，有時可以替換為as。試對比：

●He married her, which was natural.（不能插入it。為何此處不能插入it呢？因為，which是代詞，在從句中作成分，如果再插入it，則重複了。）

●He married her, as (it) was natural.（有無it都可以。為何此處有無it都可以呢？因為，as是連詞，as在從句中不作成分，所以，插入it之後，也不重複。又因為as引導的是狀語從句，而狀語從句有時可以省略無意義的主語it。）

●She has been absent again, which is expected/(which expected×).（「which+be+v-ed」時，不能插入it，也不能省略be。）

●She has been absent again, as (it) is expected/as expected.（「as+be+v-ed」時，可以插入it，也可以省略be。）

注意，which在「主謂賓」中作主語時，不能替換為as。如，He saw the girl, which/(as×) delighted him.

Tom was late for school again, which/(as×) made his teacher angry.（這兩個句子為何不能看作as從句省略it呢？因為，在狀語從句中，一般在「主系表」情況下，才可以省略it，而以上兩個句子都是「主謂賓」。）

（2）which作賓語時，有時可以替換為as。試對比：

●He is from the south, which we can know from his accent.（不能插入it）

●He is from the south, as we can know (it) from his accent.（有無it都可以）

（3）which作表語時，有時可以替換為as。試對比：

●He seemed a foreigner, which in fact he was.（不能插入a foreigner）

●He seemed a foreigner, as in fact he was (a foreigner).（有無a foreigner都可以。因為，在狀語從句中，承前省略了a foreigner。）

總之，as是連詞，which是代詞，兩者截然不同。二者能換用的情況，純屬巧合，並不能說明它們詞性相同。打個比方，一個馬群和一個牛群，偶爾在同一地方吃草，但是，馬還是馬牛還是牛。

3.常見的as引導評述性狀語從句。見下表，

註：關於狀語從句中的省略，可以參看本章第七節以及第十二章。

4. 注意as/it/what的區別。如，

●What is known to us all is that China has the largest population in the world.

（what引導主語從句，that引導表語從句）

●It is known to us all that China has the largest population in the world.

（it作形式主語，真實主語是後邊的that從句）

●As is known to us all, China has the largest population in the world.

（as引導評述性狀語從句）

分組對比練習

題組28（as與which）

1. _____ is often the case, we have worked out the production plan.（2004,江蘇）

A．Which B．When C．What D．As

分析：as引導評述性狀語從句，可以放在主句前，也可以放在主句後。which引導定語從句，不能放在主句前，只能放在主句後。選D。

2. A lot of language learning, ____has been discovered, is happening in the first year of life, so parents should talk much to their children during that period .（2012,安徽） A．as B．it C．which D．this

句意：正如研究發現，很多語言學習發生在出生後的第一年，所以，在那個階段，父母應該多和孩子說話。選A。

3. The owner of the cinema needed to make a lot of improvements and emply more people to keep it running, ____meant spending tens of thousands of pounds.(2006,江蘇) A.who B.that C.as D.which

分析：which (代詞)在從句中作成分（作主語），as (連詞)在從句中不作成分。選D。

4. If the man is only interested in your looks, ____ just shows how shallow he is. (陷阱題)

A. as B. which C. what D. that

分析：容易誤認為逗號後是非限制性定語從句，從而誤選A或B。其實，注意逗號前是一個條件狀語從句，逗號後是該狀語從句的主句，that 在此代表前文所述的情況，用作主句的主語。選D。

5. —Who should be responsible for the accident?—The boss, not the workers.They just carried out the order____.（2008,福建） A．as told B．as are told C．as telling D．as they told

分析：as (they are) told，選A。

題組29（as/it/what）

1. _____ is known to everybody, the moon travels round the earth once every month.（全國卷）

A. It B. As C. That D. What 選B。

2. The air quality in the city, ____is shown in the report, has improved over the past two months. (2012,福建) A. that B. it C. as D. what

句意：正如報告中所寫的那樣，在過去的兩個月中，這座城市的空氣質量提高了。

分析：把從句放在句首就很明白了: is shown in the report, the air quality in

3. ____ in the regulations that you should not tell other people the password of your email account.（上海高考題） A. What is required B. What requires is C. It is required D. It requires

句意：規則要求你不應把你的電子郵件的密碼告訴別人。選C。

4. ____ was most important to her, she told me, was her family. (2008,山東).

A. It B. This C. What D. As

分析：what是主語從句的引導詞，其餘都不是。選C。

5. Everyone knows that ____ is dangerous to play with fire，but ____ is difficult is to prevent children from playing with fire. (陷阱題). A. it, it B. what, what C. it, what D. what, it

分析：容易誤選A或B。其實，第一空填形式主語it，真正的主語是其後的不定式to play with fire。第二空填 what，what is difficult 是主語從句（注意到what is difficult 後有is，若沒有這個is，則第二空也填it）。答案是C。