which 引导定语从句时什么时候在前面加介词啊？
1、定语从句用which情况：
1，非限定性定语从句
2.关系代词前有介词
3.关系代词后有插入语
如：
1、The
sun
heats
the
earth
,
which
makes
it
possible
for
plants
to
grow
.
2、The
bodies
on
which
the
forces
act
are
in
equilibrium．
3、Here
is
the
English
grammar
book
which,as
I
have
told
you
will
help
improve
your
English.
2：如果第二个问题问的这两个短语还是与定语从句有关的话，那
so后面都加形容词，that后面加句子，as后面加名词。如：The
biscuits
are
so
delicious
that
I
want
to
eat
more.
订攻斥纪俪慌筹苇船俩The
food
is
not
so
good
as
those
we
ate
in
Bill's
home.
so...as用于否定句，和as...as意思一样。后者肯定句否定句都能用。
希望能帮到您！
主要是考察定语从句的问题，介词+关系代词，介词的存在取决于从句后的位于动词，若为是不及物动词则需要需要一个介词来伴随，这里write就是不及物不能直接接sb,所以需要一个指向性的介词TO
关于介词的位置问题as
following
关系代词whom,
which作从句中介词的宾语，介词一般提前，也可放在后面。但如果从句中的介词为谓语的动词短语，介词不能提前，需紧挨动词。
She
sat
on
the
corner
of
the
table
near
the
door
by
which
he
husband
always
entered.
She
sat
on
the
corner
of
the
table
near
the
door
which
he
husband
always
entered
by.
This
is
the
key
which
you
are
looking
for.
但是先行词是时间，介词应放在关系代词which之前，不放在句尾。
I’ll
never
forget
the
day
which
I
first
met
you
on.
(Χ)
如果whom,
which为介词宾语被省略，介词不能提前。
I
have
the
book
you
are
talking
about.
The
girl
he
leaned
against
was
his
sister.
eg. 1.I like the cakes which you bought on the way home.
which从句修饰的中心语“cakes” 与从句中的动词“buy” 可以直接搭配使用，buy cakes，
you bought cakes on the way home. 所以此处无需用介词；
2. I like the new pencil with which you wrote a letter just now.
中心语“pencil” 带入从句：you wrote a letter with a new pencil. 此时，which前也就相应的用上介词“with”
当定语从句中的which是做介词的宾语，就要在which前加介词。举个例子，This is the city which I lived in.或 This is the city in which I lived.在这个从句中，which就是做介词in 的宾语，所以前面一定有in。你可能觉得别扭，干嘛有in 啊？直接把which放在live后不就行了吗？ 这时你可能就没有了解一个概念 live 这个动词是不及物动词，它后面没有宾语。不能接名词。但是可以接介词短语，来做这个动词的状语（一般来说是地点状语），也就是说不及物动词后不接名词但是能够接介词短语才能和名词相见。这是个搭配模式：不及物动词+介词短语。
引用别人的，希望对你有帮助
作宾语的时候。
