文档介绍：现在完成时中“since”和“for”的区别
1) since +过去一个时间点(如具体的年、月、日期、钟点、1980, last month, half past six)。
I have been here since 1989.
2) since +一段时间+ ago
I have been here since five months ago.
3) since +从句
Great changes have taken place since you left.
Considerable time has elapsed since we have been here.
4) It is +一段时间+ since从句
It is two years since I became a postgraduate student.
Since 用来说明动作起始时间,for用来说明动作延续时间长度。
I have lived here for more than twenty years.
I have lived here since I was born..
My aunt has worked in a clinic since 1949.
Some new oilfields have been opened up since 1976.
I have known Xiao Li since she was a little girl.
My brother has been in the Youth League for two years.
I have not heard from my uncle for a long time.
注意:并非有for 作为时间状语的句子都用现在完成时。
I worked here for more than twenty years.
(我现在已不在这里工作。)
I have worked here for many years.
(现在我仍在这里工作。)
小窍门:当现在完成时+一段时间,这一结构中,我们用下面的公式转化,很容易就能排除非延续动词在完成时中的误使。
1) (对) Tom has studied Russian for three years.
= Tom began to study Russian three years ago, and is still studying it now.
2) (错) Harry has got married for six years.
= Harry began to get married six years ago, and is still getting married now.
显然,第二句不对,它应改为 Harry got married six years ago. 或 Harry has been married for six years.
声音:sound,noise 与 voice的区别
sound表示听起来像……和like连用,如:
It`s sounds like a 。
voice表示嗓音,说他的嗓音很动听,用his voice was good.
noise是杂音,响动的意思。如:我听到有动静。I heard a noise .
这是一组与“声音”有关的名词,在使用上有区别。
sound泛指自然界各种各样的声音,不论其高低、是否悦耳等。
如: I heard the sound of running water. 我听见流水声。
Light travels faster than sound. 光比声音传播得快。
noise表示“噪音、喧闹”,指的是人们不愿听到的声音或嘈杂声。它可以作可数名词,也可以用作不可数名词。如:
I heard some strange noises last night. 昨夜我听见一些奇怪的响声。
There's a lot of noise here. 这个地方人声嘈杂。
voice用于人时,指说话、歌唱或发笑的声音,也可指发言权。用于其它方面时,常含悦耳之声,如鸟鸣声,乐器声音等。如:
Please speak in a louder voice. 请大声说。
说:tell,speak,say,talk的区别
tell 意为“告诉、讲述”,指某人把某一件事、一条信息传送给别人或讲述一件事。tell sb sth 意为“告知某人某事”。 tell sb to do sth 意为“告诉某人去做某事”。
speak 意为“说话、讲话”,