if when until so 的用法及时态
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if when until so 的用法及时态
if when until so 的用法及时态
if when until so 的用法及时态
if引导条件状语从句,when引导时间状语从句!
先去看看什么叫从句
条件状语从句是表示主句动作发生的前提或条件的从句.引导条件状语从句的连词有if,unless,so/as long as,as/ so far as,on condition that,in case,suppose,supposing等.条件状语从句中的谓语动词一般要用一在时或过去时代替一般将来时或过去将来时.
if
if表示正面条件,意为“如果”.
If you ask him,he will help you.
如果你向他请求,
Difficulties are nothing if we are not afraid of them.
如果我们不怕困难,困难就算不了什么了.
until都可以用作连词和介词,用于肯定句和否定句.用于肯定句时,只与持续性动词连用,有一个not...until的形式是固定的表示"到...为止".用于否定句时,通常与瞬间动词连用,也可与持续性动词连用,表示"直到...才"的意思.这两个词一般情况下可以相互换用.例如:
We waited for him until/till six o'clock.我们等他到一直等到六点钟.
The pupils will not begin the meeting till/until their class supervisor comes.学生们等到班主任一到就开始开会.
They didn't talk until/till the interpreter came.直到译员到,他们才交谈.
He did not go to bed until/till he had made sure that nothing was wrong with the pipes.他检查水管,确准它们没有毛病,才去睡觉.
当until用于句首时,一般不能用till代替.在以not开始的从句或短语里,till一般也不可代替until,而且这种句式要用倒装语序.例如:
Until the last minute of the match we kept playing.直到比赛的最后一分钟,我们仍然坚持奋战.
Not until he had finished his work did he go home.他直到把工作做完,才回家去.
一、so作副词用,意为“这样”、“如此”,常用来代替整个句子或某一情况的全部,在口语中常与think,hope,say,be afraid等词语连用,表示客气、委婉的答语.例如:
1)—I think English is more useful than Chinese.What about you?我认为英语比汉语更有用,你说呢?
—I don't think so.I think they are both useful.我不这样想,我认为它们都有用.
2)—Will it be fine tomorrow?明天天气会好吗?
—I hope so.但愿如此.
二、so作连词用,意为“因而”、“所以”、“为了”、“以便”等.例如:
Wang Tao's pen was broken,so he needed a new one.王涛的钢笔坏了,所以他需要买枝新的.
注意:用英语表达“因为……,所以……”时,用了because就不能再用so,用了so就不能再用because.请注意下面汉语句子的英语译法:
因为他病了,所以没去上学.
误:Because he was ill,so he didn't go to school.
正:Because he was ill,he didn't go to school.
正:He was ill,so he didn't go to school.
三、so用作副词,在句中可以修饰形容词或副词.
1.so表示程度,意为“这么”、“那么”、“如此地”.例如:
When he came back,I was so tired.当他回来的时候,我疲劳极了.
2.so常用于口语,意为“非常”、“很”.例如:
—I found it in my bag five minutes ago.五分钟前我在我的包里找到了它.
—I'm so glad.我很高兴.
3.在“so+助动词/be动词/情态动词+主语”的倒装结构中,表示前面所述的肯定情况也适合于后者.例如:
I'm good at English,and so is my sister.我英语学得好,我妹妹学得也好.
I like English and so does she.我喜欢英语,她也喜欢.
注意:在这一结构中的主语可以是名词或人称代词,但它和上文的主语不是同一个“人”或“物”.例如:
—She bought a computer.她买了一台电脑.
—So did I.我也买了一台.
另外,这一结构的否定式是“neither/nor+助动词/be动词/情态动词+主语”.例如:
—He doesn't know Lin Tao's address.他不知道林涛的地址.
—Neither do I.我也不知道.
这里的neither/nor意为“也不”或“也没有”.
4.在“so+主语+助动词/be动词/情态动词”结构中,so用于对前面事实的肯定,有“的确如此”之意.例如:
—He will go to Hangzhou for a holiday tomorrow.他明天要去杭州度假.
—So he will.的确如此.
注意:这一结构中的主语和上文中的主语通常是同一个“人”或“物”.又如:
—It's her turn now.现在轮到她了.
—So it is!是呀!
5.在“主语+do(动词某种形式)+so”结构中,so用以避免重复前文提到的情况.例如:
The teacher asked us to read the text and we did so.老师让我们读这篇课文,我们就读了.