第1个回答 2019-01-17
引导主语从句连词有that,whether,who,what,whatever等
定义:如果一个句子在复合句中充当一个主语,那么这个句子就是主语从句.
第一部分：常规主语从句，即句子在复合句中充当一个主语
（1）That
he
finished
writing
the
composition
in
such
a
short
time
surprised
us
all.
（2）Whether
we
will
go
for
an
outing
tomorrow
remains
unknown.
（3）Who
will
be
our
monitor
has't
been
decided
yet.
（4）
Whom
we
must
study
for
is
a
question
of
great
importance.
（5）What
caused
the
accident
remains
unknown.
（6）Whatever
you
did
is
right.
（7）Whose
watch
was
lost
is
unknown.
（8）What
we
need
is
time.
（9）What
we
need
are
good
doctors.
小结:
（1)引导主语从句连词有that,whether,who,what,whatever等
（2)连词位于句首不能省略
（3)主语从句大多数情况下视为单三,但也有例外,如例9
第二部分：为了防止句子头重脚轻，通常把形式主语it放在主语位置，真正主语搁置于句末
（1）It
is
certain
that
he
will
win
the
match.
（2）It
is
true
that
he
has
made
a
very
important
discovery
in
chemistry.
（3）It
is
very
likely
that
they
will
hold
a
meeting.
（4）It
is
strange
that
he
should
do
that.
（5）It
is
important
that
we
all
should
attend
the
meeting.
（6）It
is
strange
that
the
man
should
have
stuck
to
his
silly
ideas.
（7）It
is
a
pity
that
we
won't
be
able
to
go
to
the
south
to
spend
our
summer
vacation.
（8）It
is
still
a
mystery
what
caused
the
accident.
（9）It
is
said
that
he
has
gone
to
shanghai.(=He
is
said
to
have
gone
to
shanghai)
（10）It
is
known
to
all
that
the
gun
powder
was
first
invented
by
the
Chinese.
（11）It
is
suggested
that
the
work
should
be
done
with
great
care.
（12）It
seems
that
he
has
seen
the
film.(=He
seems
to
have
seen
the
film)
（13）It
happened
that
the
two
cheats
were
there.
(=The
two
cheats
happened
to
be
there)
小结:
（1)以that
引出的主语从句,常以形式主语it引导.
It
is
+形容词/名词/某些动词ed
+
that
从句.
（2)
在有些that从句中要用虚拟语气
(should+do/should+have
done)例句4,5,6,11.