第1个回答 2008-04-03
你好,UNTIL可以是介词,也可以是连词。做介词的用法我就不说了,查字典可以查到。做连词,分为肯定句和否定句两种情况。
只有在否定句中,才出现需要区分UNLESS和UNTIL的情况。
从词义上理解,until是指“直到……才”,unless是指“除非……”、“如果不”、“要是不”。until 一般用于完成时。unless = if not,在做题的时候可以将它转化为if not来理解。
该题只需根据词义即可解决,将它解释为除非老师来否则我们做不出这题显然不通,因为时态都不对。
参考资料: A:
连接词主要有 if, unless, as/so long as, on condition that 等。.
if 引导的条件句有真实条件句和非真实条件句两种。非真实条件句已在虚拟语气中阐述。
unless = if not.
Let's go out for a walk unless you are too tired.
If you are not too tied, let's go out for a walk.
典型例题
You will be late ___ you leave immediately.
A. unless B. until C. if D. or
答案A。 句意:除非你立即走,否则你就回迟到的。可转化为 If you dong leave immediately, you will be late. B、D句意不对,or表转折,句子如为 You leave immediately or you will be late.
时间状语从句:
状语从句需要连词引导。引导时间状语从句的连词有: when,while,as,as soon as,before,once,after, since,till/until等。 例如:
When you finish doing this drill, you may go on to the next one.
I'll let you know as soon as it is settled.
She has written fifty letters home since she came to Beijing.
注意(一): 虽然till和until可互相交换使用。但在句首只能用until。
用于否定句时,表示“直到…时,才…”;“在…以前,不…”例如:
Until you told me about the book I had no idea of it.
(在你告诉我之前,我对此书一无所知。)
I won't know where he is until I get a letter from him.
(收到他的信时我才知道他在那里。)
时间状态语从句中用一般现在时表示将来时间,用现在完成时表示将来完成时间。例如:
As soon as my brother arrives, we'll start working.
第2个回答 2019-04-30
unless和until的用法区别。一、作为从属连词含义不同,引导从句性质不同unless与until均为从属连词,unless表“除非”,强调条件,引导条件状语从句;until表“直到”,强调时间的延续,引导时间状语从句。1.
I
didn't
know
the
news
until
my
teacher
told
it
to
me.
2.
I
couldn't
know
the
news
unless
my
teacher
told
it
to
me.3.-Was
his
father
very
strict
with
him
when
he
was
at
school?
-Yes.
He
had
never
praised
him
until
he
became
one
of
the
top
students
in
his
grade.
析:句1动词didn't
know表明该句强调时间的延续,表“我不知道这消息”的状态一直延续到“老师告诉我”,因此应用until引导时间状语从句。句2动词couldn't
know表明该句强调条件,表“我不可能知道这消息,除非老师告诉我”,因此应用unless引导条件状语从句。句3表明“他爸爸从来没有表扬他”的状态一直延续到“他变成年级最好的学生之一”,因此也应用until引导时间状语从句。二、作为从属连词引导的从句常用一般现在时表示将来unless引导的条件状语从句和until引导的时间状语从句常用一般现在时表示将来。例1:除非邀请你否则别进来。误:Don't
come
in
unless
you
will
be
invited
to.正:Don't
come
in
unless
you're
invited
to.例2:除非他来,我们不可能去。误:Unless
he
will
come,
we
won't
be
able
to
go.正:Unless
he
comes,
we
won't
be
able
to
go.三、作为从属连词引导的状语从句可转换为省略式创新句型unless引导条件状语从句和until引导时间状语从句时,如果主从句主语一致(或主从句主语不一致,但从句主语为it),从句谓语部分含有be,可将从句主语和动词be省略,构成省略式创新句型。例1:I
won't
come
to
see
you
unless
I
am
asked
to.
除非你邀请我,我才会来看你。析:因为主从句主语一致,从句谓语又含有am,所以可将从句主语I和动词am
省略,构成省略式创新句型:I
won't
come
to
see
you
unless
asked
to.例2:The
soldiers
will
not
cross
the
river
unless
they
are
ordered
to.
除非接到命令,战士们不会过河。析:因为主从句主语一致,从句谓语又含有are,所以可将从句主语they和动词are省略,构成省略式创新句型:The
soldiers
will
not
cross
the
river
unless
ordered
to.注意:until也可作为介词。例如:I
have
remembered
her
until
now.
直到现在我还记得她。
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