您好，楼主，希望我的答案对您有帮助！
答案：强调句与从句的比较1.
强调句与主语从句的比较强调句将句子中的it
is
/
was
…that同时省去，句子仍然成立；而主语从句将that与后面部分代替it，成立。如：(1)
It
is
Li
Lei’s
brother
that
you
met
in
the
street
yesterday.
你昨天在街上所见到的就是李蕾的兄弟。本句若将It
is
及
that同时省去为：You
met
Li
Lei’s
brother
in
the
street
yesterday.
句子同样成立，因此前面的句子是强调句型。(2)
It
is
exciting
that
we
have
succeeded
in
sending
up
Shenzhou
V.
我们成功地发射了神舟五号这件事情真令人兴奋。本句若将It
is
及
that同时省去为：We
have
succeeded
exciting
in
sending
up
Shenzhou
V.
显然句子错误，因此，前面句子不是强调句型，而是主语从句。2.
强调句与定语从句的比较◎强调句中的It没有实际意义，It
be与that可同时被省略；而定语从句中的It是主语，It
be与that不可同时省略；◎强调句型中be的时态须跟后面句子的时态相一致；而定语从句中主句谓语动词be的时态须由主句的时间确定(from
www.yygrammar.com)；◎强调句将句子中的that不能省略，并且即使前面的名词是事物时，也不能将that换成which；而定语从句中的that作宾语时可被省略，并且当先行词是事物时可用which代替。◎当it
be后面的时间、地点名词作主语、宾语或表语时，引导词可用that
/
which；而作其他成分时，引导词须用when
/
which。如：(1)
It
is
an
English
book
(that
/
which)
I
bought
yesterday.
它是我昨天买的书。(本句是对What
is
that?问句的回答，that所引导的是定语从句，that可被省略)
It
was
the
English
book
that
I
bought
yesterday.
昨天我所卖的就是这本书。(本句相当于对I
bought
the
English
book
yesterday中an
English
book进行强调)
(2)
It
was
a
room
where
we
used
to
have
meetings.
它是我们过去常在开会的房子。(where
所引导的从句对前面的room进行说明，它是定语从句)It
was
in
the
room
that
we
used
to
have
meetings.
过去我们开会就在这间房子里。(in
the
room是被强调的部分，本句是强调句型)
(3)
It
is
a
day
when
the
people
celebrate
their
victory.
这是人们庆祝他们的胜利的日子。
(when所引导的从句对a
day进行说明，是定语从句)
It
was
on
that
day
that
people
celebrated
their
victory.
就在那一天，人们庆祝了他们的胜利。(强调on
October
1,
1949)
3．强调句与状语从句的比较◎状语从句句首的It本身就是句子的主语；而强调句首的It不作任何成分也没有实际意义。◎状语从句的连接副词that及句子前面的It
be不能去掉(from
www.yygrammar.com)。◎状语从句的引导词可以是when
/
where，而强调句型中的that不能用其他词代替。如：(1)
It
is
such
an
interesting
book
that
we
all
like
it
very
much.
它是一本如此有趣的书，我们大家都非常喜欢。(结果状语主从复合句)
It
is
such
an
interesting
book
that
we
all
like
very
much.
我们大家都非常喜欢的就是一本如此有趣的书。(强调such
an
interesting
book)
(比较：It
is
such
an
interesting
book
as
we
all
like
very
much.
这就是我们大家都非常喜欢的如此有趣的书。定语从句)(2)
It
was
already
morning
when
he
woke
up.
当他醒来时，已经是早晨了。(时间主从复合句)It
was
the
next
morning
that
he
woke
up.
就在第二天早晨他醒来了。(强调the
next
morning)
祝：
您的英语水平不断提高
！