英語講義【80】形容詞從句的位置
在《容易犯錯的形容詞從句》一文里，知道形容詞從句總是跟在被修飾的名詞（即先行詞）后面。例如：
① Any change which causes the formation of new matters is a chemical change.（在主句主語的名詞之后）
② Plastics is an important material which is widely used in industry.（在主句補足語名詞之后）
③ It has certain features that are easily recognised.（在主句賓語名詞之后）
在下列情況下，形容詞從句和所修飾的名詞隔開：
㈠被介詞短語隔開，如：
④ Magnets work through lines of force that extend between the two ends of the magnet.
⑤ A molecule may be defined as the smallest particle of matter that can exist without changing its nature.
④里的形容詞從句和先行詞lines被介詞短語of force 分離。⑤里的卻被另一個介詞短語of matter隔開。
㈡被分詞短語隔開，如：
⑥ There is no method known to medical science today that can effectively cure cancer.
⑥里的形容詞從句和先行詞method之間被過去分詞短語 known to medical science today隔開。
上述兩種隔離情況可以理解，也被接受。
另外還有一種分隔情況，也偶爾見到，特別在科技英語中，但這種離異法，值得商榷。
例如：
⑦ Several other ideas came along that enabled engineers to design still smaller units.
⑧ Ninety-six substances are known which chemists consider to be elements.
⑦和⑧里的形容詞從句和先行詞ideas及substances之間都被主句的謂語動詞came along和are known分開。
這類的分隔情況，多在主句謂語動詞是被動語態(tài)（the passive voice）時才出現(xiàn)，如例⑧，但謂語動詞是主動語態(tài)（the active voice）的話，也可以，如例⑦，只是數(shù)量少些。
為什么要把形容詞從句常見的位置和先行詞分開呢？主要原因是：先行詞所在的主句較短，而修飾先行詞的形容詞從句則很長。為了平衡主句和從句，才采用這方法。雖然如此，但它和一般的形容詞從句的位置有很多抵觸，恐怕引起混亂。
為了減少不必要的麻煩，最好改用別的句式。其中一個方法是將形容詞從句改為另外一個獨立的簡單句（如例⑨╆）；另一個辦法是采用并列句（如例⑩╇）：
⑨ Several other ideas came along. Such ideas /They enabled engineers to design still small units.
⑩ Several other ideas came along and these ideas enabled engineers to design still small units.
╆ Ninety-six substances are known. Chemists consider them to be elements.
╇ Ninety-six substances are known and chemists consider them to be elements.
在《容易犯錯的形容詞從句》一文里，知道形容詞從句總是跟在被修飾的名詞（即先行詞）后面。例如：
① Any change which causes the formation of new matters is a chemical change.（在主句主語的名詞之后）
② Plastics is an important material which is widely used in industry.（在主句補足語名詞之后）
③ It has certain features that are easily recognised.（在主句賓語名詞之后）
在下列情況下，形容詞從句和所修飾的名詞隔開：
㈠被介詞短語隔開，如：
④ Magnets work through lines of force that extend between the two ends of the magnet.
⑤ A molecule may be defined as the smallest particle of matter that can exist without changing its nature.
④里的形容詞從句和先行詞lines被介詞短語of force 分離。⑤里的卻被另一個介詞短語of matter隔開。
㈡被分詞短語隔開，如：
⑥ There is no method known to medical science today that can effectively cure cancer.
⑥里的形容詞從句和先行詞method之間被過去分詞短語 known to medical science today隔開。
上述兩種隔離情況可以理解，也被接受。
另外還有一種分隔情況，也偶爾見到，特別在科技英語中，但這種離異法，值得商榷。
例如：
⑦ Several other ideas came along that enabled engineers to design still smaller units.
⑧ Ninety-six substances are known which chemists consider to be elements.
⑦和⑧里的形容詞從句和先行詞ideas及substances之間都被主句的謂語動詞came along和are known分開。
這類的分隔情況，多在主句謂語動詞是被動語態(tài)（the passive voice）時才出現(xiàn)，如例⑧，但謂語動詞是主動語態(tài)（the active voice）的話，也可以，如例⑦，只是數(shù)量少些。
為什么要把形容詞從句常見的位置和先行詞分開呢？主要原因是：先行詞所在的主句較短，而修飾先行詞的形容詞從句則很長。為了平衡主句和從句，才采用這方法。雖然如此，但它和一般的形容詞從句的位置有很多抵觸，恐怕引起混亂。
為了減少不必要的麻煩，最好改用別的句式。其中一個方法是將形容詞從句改為另外一個獨立的簡單句（如例⑨╆）；另一個辦法是采用并列句（如例⑩╇）：
⑨ Several other ideas came along. Such ideas /They enabled engineers to design still small units.
⑩ Several other ideas came along and these ideas enabled engineers to design still small units.
╆ Ninety-six substances are known. Chemists consider them to be elements.
╇ Ninety-six substances are known and chemists consider them to be elements.
