unless的用法

Question

给我一些关于unless正确的用法
还有unless可不可以用在开头?
例,
unless i work hard and hold it on,I won't go to the NO.1 high school.
这句话对吗?

Answer 1

应该是对的。
Unless I work hard and hold it on,I won't go to the NO.1 high school.
也可以这样写：
I won't go to the NO.1 high school unless I work hard.

Answer 2

U6-4:An old man tried to move the mountains.知识点4unless引导的时间状语从句

Answer 3

我估计你要问得是before和until的区别

实际上，只要我们把握住两者使用时本身的含义及主句动词是终止性的，还是延续性的，肯定式，还是否定式两大点，就能容易地解决这类问题。现详细阐明如下：
一、在下列情况下，两者可互换用，但含义略有不同。before表示“在……之前”的意思，强 调时间先后关系；而until表示“直到……才”的意思，主句是肯定句则表示主句动作的终 止时间；主句是否定句则强调主句动作的起始时间。
1.主句为否定式终止性谓语动词。常见的动词是open,start,leave,arrive,finish,
stop等。例如：
(1)The noise of the street didn't stop until/before it was midnight.
(2)The children won't come back until/before it is dark.
(3)I didn't leave the lovely boy until/before his mother came home.
2.主句为肯定式、延续性谓语词，这类动词用stand,stay,talk,be,wait等。例如：
(1)He lived with his parents until/before he graduated from school.
(2)I will wait until/before he comes to my help.
(3)I shall stay heer until/before you come back.
二、在下列情况下，用before不用until。
1.主句这肯定式、终止性谓语动词，只用before。例：
(1)He fell asleep before I could take off his clothes.
(2)We arrived there before it atarted to rain.
(3)The holiday came to the end befor I knew it.
(4)He almost knocked me down before he saw me.
2.主句谓语动词强调动词的迟缓性，只用before，常伴有时间段状语或时间段暗示。例：
(1)It was quite some time before he found the elephant at all.
(2)We had walked a long way before we found some water.
(3)We had sailed for two days before we saw the land.
(4)The fire lasted about four hours before the firefighters could
countrol it.
(5)It was midnight before my brother came home.
(6)It was three months before they met again.
3.如果强调从句谓语动作未发生，就发生主句谓语动作，只用before。常译为“未及”，“不”或“不等……就”。例：
(1)We can leave early in the morning before it gets too hot.
(2)I must write it down before I forget it.
(3)We do want to buy something now before prices go up.
4.表“与其说……倒不如”，“与其……毋宁……”只用before。例：
(1)I would give up my job before I'd agree to be dismissed.
(2)He will die of hunger before he will steal.
5.在某些特定句型中用before。例如：
(1)It was not long before the whole country rose up.
(2)It will probably not be long before they understand each other.
三、下列情况一般区别用until。
1.主句是持续性谓语动词时，肯定、否定都可以，但意义完全不同。肯定表动作终止，而否定表动作开始。例如：
(1)We discussed the problem until/before he came back.我们一直讨论到他回
来。
(2)We didn't discuss the problem until he came back.我们一直等到他回来后才讨论问题。
2.not…until句型尽管在某些情况下可与before互换用，但在强调句中一般仍用until。
例如：
(1)It was not until he told me that I knew it.
(2)It was not until he finished his homework that he went home.

Answer 4

unless是从属连词，引导条件状语从句，含有否定意义，相当于if条件状语从句的否定形式。所以unless
=
if
not。注意：unless引导的条件状语从句和if条件状语从句，与其它时间状语从句一样，用一般现在时代替将来时。

Answer 5

unless 除非，如果不，等于“if not”本身就表示否定，引导条件状语从句，主句为将来时，条件状语从句用一般现在时表示将来。

例：My baby sister doesn’t cry unless she’s hungry.

=My baby sister doesn’t cry if she isn’t hungry.

Unless you take more care, you’ll have an accident. 如果你不多加小心的话，你会出事的。