by的被动语态怎么造句?宾语从句的语法

如题所述

by+sb.

宾语从句语法要点
  一、当由陈述句充当宾语从句时,用that引导,that无词义,在口语或非正式文体中常省略。如:
  She said that she would leave the message on the headmaster's desk.
  He said that he could finish his work before supper.
  二、当由一般疑问句充当宾语从句时,用if或whether引导,意为“是否”。如:
  Alice wanted to know if/whether her grandmother liked the bag.
  I don't know whether he'll come the day after tomorrow.
  但直接与or not连用时,往往用whether如:
  Let me know whether he will come or not.(= Let me know whether or not he will come )
  I don't know whether he does any washing or not.(= I don't know whether or not he does any washing. )
  I wonder whether we stay or whether we go.
  三、如果宾语从句原来是特殊疑问句,只需用原来的疑问词引导。如:
  Could you tell me where we will have the meeting this afternoon?
  I don't know who bought the present for me. Is it Jack?
  宾语从句是初中阶段一个非常重要的语法项目。宾语从句也是历年全国各地中考必考项目之一,考查点涉及到"语序"、"时态"、"引导词"三个要素。而宾语从句的时态。语序是中考题的热点。
  宾语从句热点问题:
  ①宾语从句一般要用陈述句语序,即主语之后接谓语动词?例如:Can you find out where he lives(不说where does he live)。
  ②主句谓语动词为一般过去时,则宾语从句通常要用过去的某种时态。不过,若宾语从句所叙述的是客观事实,普遍真理,自然现象等时,要用一般现在时.例如:Our teacher said light travels faster than sound.
  ③连词that引导由陈述句充当的宾语从句,that在句中不充当任何成分,在口语和非正式文体中常可省略;
  ④主句谓语是一般现在时,宾语从句可根据需要使用任何时态。例如:Nobody knows where he was born.没有人知道他出生在哪儿。
  ⑤主句谓语动词是guess, think或believe等,且主句主语是第一人称时,从句的否定概念一般要转移到主句中去,即"否定转移"。例如:I don't think he is a good student. (不说I think he isn't a good student.)我认为他不是个好学生。
  ⑥不少中考题是将两类从句(宾语从句与状语从句的区别)综合起来考查的。这时要注意:
  A.从句式看,宾语从句只能放在主句谓语动词之后,而状语从句一般可以放在主句的前面或后面;
  B.从引导词看,if充当宾语从句的引导词时,相当于whether,词义为"是否";
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第1个回答  2012-03-22
by后面加的是做这个动作的人,如果你在句中要告诉别人谁做了这个动作,那就by+sb
They are planting trees over there. →
Trees are being planted over there by them.
第2个回答  2012-03-25
被动语态往往只强调事情发生的动作和结果,而不强调发起动作的人。
He watered the flowers yesterday.
The flowers was watered (by him) yesterday.
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