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。
标签:从句,限制性,定语