Question

we are living in an age( )many things are done on computers a which b that c where d when

还有一道类似的也不太明白 we are living in an age（ which或that） we have a lot of things to learn about 第一道为什么不能用that或which. 第二道为什么不能用when 介词+关系代词（which）=where或when怎么理解

Answer 1

第一个句子后面的从句少了
时间状语
，所以引导词用的是when，后面的句子完整的话就是Many
things
are
done
on
computers
in
the
age.你看后面这个句子不少
主谓宾
，只是少状语。
而第二个句子后面的从句少了宾语，所以引导词是which/that，后面的句子完整的话就是We
have
a
lot
of
things
to
learn
about
this
age.
所以用which/that
指代an
age
介词+
关系代词
（which）=where/when
我可以举个例子
I
like
the
room
where
he
lives=I
like
the
room
in
which
he
lives.
这里where指代in
the
room
which
指代the
room
I
like
Saturday
when
I
can
play
games=
I
like
Saturday
on
which
I
can
play
games
这里when指代on
Saturday
which
指代Saturday。