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发表于 2017-8-5 23:23:58
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(三) 限制性和非限制性定语从句
(1)定语从句有限制性和非限制性两种。限制性定语从句是先行词不可缺少的部分,去掉它主句意思往往不明确;非限制性定语从句是先行词的附加说明,去掉了也不会影响主句的意思,它与主句之间通常用逗号分开。例如:
·This is the house which we bought last month.
这是我们上个月买的那幢房子。(限制性)
·The house, which we bought last month, is very nice.
这幢房子很漂亮,是我们上个月买的。(非限制性)
(2) 当先行词是专有名词或物主代词和指示代词所修饰时,其后的定语从句通常是非限制性的。例如:
·Charles Smith, who was my former teacher, retired last year.
查理·史密斯去年退休了,他曾经是我的老师。
·My house, which I bought last year, has got a lovely garden.
我去年买的那幢房子带着个漂亮的花园。
· This novel, which I have read three times, is very touching.
这本小说很动人,我已经读了三遍。
(3) 非限制性定语从句还能将整个主句作为先行词, 对其进行修饰, 这时从句谓语动词要用第三人称单数。例如:
·He seems not to have grasped what I meant, which greatly upsets me.
他似乎没抓住我的意思,这使我心烦。
·Liquid water changes to vapor, which is called evaporation.
液态水变为蒸汽,这就叫做蒸发。
说明:关系代词that和关系副词why不能引导非限制性定语从句。
(四) 介词+关系词
(1)介词后面的关系词不能省略。
(2)that前不能有介词。
(3)某些在从句中充当时间,地点或原因状语的"介词+关系词"结构可以同关系副词when 和where 互换。例如:
·This is the house in which I lived two years ago.
↓
这是我两年前住过的房子。
↑
·This is the house where I lived two years ago.
·Do you remember the day on which you joined our club?
↓
还记得你加入我们俱乐部的那一天吗?
↑
·Do you remember the day when you joined our club?
(五) as, which 引导的非限定性定语从句
由as, which 引导的非限定性定语从句,as和which可代整个主句,相当于and this或and
that。As一般放在句首,which在句中。例如:
·As we know, smoking is harmful to one's health.
如我们所知,吸烟有害健康。
·The sun heats the earth, which is very important to us.
太阳使地球暖起来,这对我们人类很重要。
【特别提示】 as
和which在引导非限制性定语从句时,这两个关系代词都指主句所表达的整个意思,且在定语从句中都可以做主语和宾语。但不同之处主要有两点:
a)as 引导的定语从句可置于句首,而which不可。
b)as 代表前面的整个主句并在从句中做主语时,从句中的谓语必须是系动词;若为行为动词,则从句中的关系代词只能用which.。
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