虚拟语气是一项语法难点，为了让学员们便于理解与记忆，我们把虚拟语气分成三大块来讨论：
1．名词从句中的虚拟语气
标志词+should+动词原形
2．条件从句中的虚拟语气
①三种基本态
②倒装虚拟句
③混时虚拟句
④含蓄虚拟句
⑤跳层虚拟句
3．其它情形中的虚拟语气（wish/would
rather/It’s
high
time…/If
only…/lest）
一．三种基本形态（1）
表虚拟的时间
if从句谓语形式
主句谓语形式
现在：
did
/
were
would
(should,
might,
could)+do
过去：
had
done/
had
been
would
(should/might/could)+have
done(been)
将来：
were
to/
should+do
would
(should,
might,
could)+do
三种基本形态（2）（这是基础，建议牢记下面的例句，争取能脱口而出）
与现在事实相反：If
I
had
enough
money,
I
would
buy
a
book.
与过去事实相反：If
I
had
had
enough
money,
I
would
have
bought
a
book.
与将来事实相反：If
I
were
to
have
enough
money,
I
would
buy
a
book.
If
I
should
have
enough
money,
I
would
buy
a
book.
二、倒装虚拟句（只能与过去/将来事实相反，省去if，只有三种倒装形式）
Had
I
had
enough
money,
I
would
have
bought
a
book.
Were
I
to
have
enough
money,
I
would
buy
a
book.
Should
I
have
enough
money,
I
would
buy
a
book.
三、混合时间虚拟语气（主要是抓住时间状语）
(对过去事实虚拟+对现在事实虚拟)
If
I
had
studied
English
at
school,
I
could
read
the
English
novel
now.
(对现在事实虚拟+对过去事实虚拟)
If
she
were
not
so
careless,
she
wouldn’t
have
made
such
a
mistake.
四、含蓄虚拟句（在四级考试中目前还未出现此考点，但在阅读中常见）
3.
虚拟语气用在主语从句中。在句型“It
is
important
(necessary,
strange,
natural等)
that...”
中，that
后面的从句中的谓语动词用(should)
+
动词原形。
It's
necessary
that
we
should
have
a
walk
now.
我们现在有必要出去散散步。
What
would
I
have
done
without
you?
But
for
their
help,
I
would
not
have
finished
the
task.
But
that
the
doctor
arrived
on
time
that
day,
they
would
have
been
dead.
Given
more
time,
I
would
have
been
able
to
finish
the
test.
五、跳层虚拟句（即句子一半为虚拟，另一半为陈述语气；but前句用虚拟而or/otherwise后句用虚拟）
(but)
He
would
put
on
weight,
but
he
doesn't
eat
much.
(与现在事实相反)
He
would
have
put
on
weight,
but
he
didn't
eat
much.
(与过去事实相反)
(or,
or
else,
otherwise)
I
forget
where
I
read
the
article,
or
I
would
show
it
to
you
now.
(与现在事实相反)
Mary
couldn't
have
received
my
letter,
otherwise
she
would
have
replied
before
now.
(与过去事实相反)
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