Question

by的被动语态怎么造句？宾语从句的语法

Answer 1

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";

Answer 2

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.

Answer 3

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.