第1个回答 2019-09-25
i:
最基本的虚拟语气句型:
1.
虚拟现在时表示与现在事实相反的假设，其if
从句的谓语形式用动词的过
去式(be
一般用were)，主句用would/
should/
could/
might
+动词原形。
if
places
were
a
like,
there
would
be
little
need
for
geographers.
如果各个地方都一样，就不需要地理学家了。
2.
虚拟过去时是表示与过去事实相反的假设，if
从句的谓语形式用过去完成时
即had＋过去分词，主句用would
/
should
/
could
/
might
+
have
+过去分词。
if
he
had
known
your
address
yesterday,
he
would
have
telephoned
you.
3.
虚拟将来时是表示对将来实现的可能性很小的或不确定的假设。if从句的谓
语形式用一般过去式或用were
to
/
should
+动词原形，主句用would
/
should
/could/
might
+动词原形。
if
he
were
to
leave
today,
he
would
get
there
by
friday
4.
省略if
采用倒装语序的条件句。
有时可以把含有助动词、情态动词、be或have的虚拟条件句中的连词if
省去，而将had
,
should,
were
等
词
提到主语之前，即用倒装结构。
had
he
worked
harder,
he
would
have
got
through
the
exams.
were
he
to
leave
today,
he
would
get
there
by
friday.
were
i
in
your
place,
i
wouldn’t
do
that
5.
有时虚拟条件句并没来if
从句表示出来，而是用介词短语(otherwise,
or,
without,
but
for)、上下文或其它方
式来表示。
we
didn't
know
his
telephone
number;
otherwise
we
would
have
telephoned
him.
without
you
help,
i
wouldn’t
have
achieved
so
much.
but
for
your
help,
i
would
not
have
succeeded.