before，after，until的用法与区别?

Question

如题所述

Answer 1

before
在...以前
after
在...以后
until
直到
before的用法：
1．
before用作连词时，意思是“在……之前；还没来得及
……
就”。例如：
Before
she
could
move,
she
heard
a
great
noise,
which
grew
to
a
terrible
roar.
她还没来得及动弹，就听见有很响的声音，接着就成了可怕的隆隆轰鸣声。
Before
I
could
say
a
word,
she
had
stormed
out
of
the
room.
不等我说一句话，她就冲出了房间。
Don’t
count
your
chickens
before
they
are
hatched.
不要高兴得过早。
2．
用于It
+
be
+
时间段
+
before...句型中，意思是“在……之后才……”。例如：
It
will
be
five
years
before
I
come
back.
我五年后才能回来。
after用法:
(1)介词:
(a)
Please
come
to
my
house
after
dinner.晚饭后
(b)
He
ran
after
the
bus.
追赶
(c)
His
mother
waited
for
him
night
after
night.（一个）接着（一个）
(d)
It's
sad
to
fail
after
all
that
work.
由于
(e)
They
are
still
friends
after
all
their
differences.
(2)
副词:
(a)
three
hours
after;
(b)
departed
shortly
after;
(c)
after
all
I
don't
really
know
him.
终究
(d)
He
told
me
afterwards
that
he
had
not
enjoyed
the
film.
后来
(3)连词:
(a)
I
saw
them
after
I
arrived.后来
(b)
They
arrived
soon
after.
后来
(c)
tomorrow,
or
the
day
after...
(4)
名词:
(a)
afternoon午后;
(b)
afterthought事后的想法;
(c)
aftermath后果
until的用法
until可用作介词或连词，意为“到……时候为止”、“到……时候才”或“在……时候以前不”。
1.
如果主句中的谓语动词是终止性动词，应采用“...
not
...
until
...”结构，意为“……到……时候才……”。例如：
You
mustn’t
eat
anything
until
you
see
the
doctor.
看过医生之后，你才能吃东西。
2.
如果主句中的谓语动词是延续性动词，那么谓语动词用肯定式或否定式，它们所表达的意思有所不同。
1）
如果谓语动词为肯定式，则until译为“到……时候为止”。例如：
I
watched
TV
until
she
came
back.
我看电视一直看到她回来。
2）
如果谓语动词为否定式，则until应译为“到……时候才”，即“在……以前不”。如：
I
did
not
watch
TV
until
she
came
back.
（=
I
began
to
watch
TV
when/after
she
came
back.）
直到她回来我才开始看电视。
3.
用终止性动词作谓语时，
until既可以和not连用，又可以和never，
nobody，
nothing，
few，
little，
seldom，
hardly等含否定意义的词连用。例如：
I
had
not
seen
him
until
1990.
（=
I
had
never
seen
him
until
1990.）
1990年以前我从未见过他。
Don’t
put
off
until
tomorrow
what
you
can
do
today.
（=
Never
put
off
what
you
can
do
today
till
tomorrow.）
今日事，今日毕。