三线合一定理

如图6所示电路中,当开关S1、S2均闭合后,则L1、L2都不能发光这是为什么? 一种声光报警器的电路如图1所示．闭合开关S1和S2后,会出现的现象是（ ）A．灯亮,铃不响 B．灯不亮,铃不响 C．灯亮,铃响 D．灯不亮,铃响 选哪个.为什么. 如图2所示的电路中,⑴当只闭合开关S1时,哪些灯发光?其等效电路如何?⑵当开关S1和S2同时闭合时,哪些灯发光?其等效电路如何?红色部分是老师分析时加的,是怎么来的?老师好像（注意!是好像, 有的函数带个绝对值来着``怎么弄呢'y=|x-2|(x+1)是不是先把| |里面的分为>0 < 0来分`?请高手赐教了```` 最好有图`` 高中数学（函数图像相关）怎样作出这个图像? 如图所示电路,电源电压不变,当开关S闭合、S1、S2断开时,电流表的示数为I1,电压表的示数为U1；当开关S、S1、S2都闭合时,电流表的示数为I2,电压表的示数为U2．则下列说法正确的是（　　）A． 如图所示电路中,电源电压为3V,且保持不变.当闭合开关S,断开开关S1时,电流表的示数如图所示电路中,电源电压为3V,且保持不变．当闭合开关S,断开开关S1时,电流表的示数为0.1A,则电阻R2则电阻R2 英语改错,如下：1:This is an art lesson. ______2:What is shape is the moon? ______3:My parents has twocars. ______ 对下列英语句改错1) To get from home to school take me 25 minutes2)I forget where did I put my book3)There is going to have a sprots meeting next week 如图所示的电路中,R2=4Ω,若只闭合开关S1,电流表的示数为0.5A;只闭合开关S2,电流表的示数为1.5A,则电路两端的电压为_____V,电阻R2的阻值为_____Ω.不知道是不是题出错了,是一本叫名校课堂的题. 如图所示的电路中,R2=40欧,电源电压不变,仅闭合开关S,电流表的示数为0.2A,再闭合开关S1,电流表增大到1A则R1的阻值为 欧,电源电压为 V 哪个成语表示非常安静 一种零件长5毫米,把它画比例尺是10：1的图纸上,应画（ ）厘米? 一个零件的长度是1.5厘米,画到一张比例尺是12:1的图纸上,要画多少分米? When a post office handles large quantities of mail daily,it is essential that mechanical methods are used to maintain production and ensure prompt delivery of the mails答案说are used 要改成 be used 为什么? 一道英语改错题Before he was a teacher,Bob told me what he 1.would like to be a lawyer when he was at school.2.He had worked very hard at his lessons and tired 3.enter into a famous university,but something unhappy 4.happened in his family,that compare with life on earth ,life on Mars will be better in many ways meals on Mars will probably in the form of pills every students will have a computer at home connect to an inter-planetary networkscientists will develop plants can grow on Mars （ ）___ 1 I A(can't) B(study) because she C(makes) D(much too) noise( ) ___ 2 A A(noise) classroom B(is not) good C(for) our D(study)( ) ___ 3 A(peter and I) are B(interesting) in C(feeding) D(animals)( ) ___ 4 The pet A(with) long ears B(eat) C(a 形容遇到危险时神态沉着冷静的成语是?形容遇到危险时神态沉着镇定.（ ）根据意思填词. 英语好的请看一下下面的两道改错题!@The great writer died for 4 years.This is so an amazing thing. 改错,哪位英语好德,赶快来帮下忙,一、判断下列句子是否正确,不正确的请改正.1.I was looking television at 5 p.m.this afternoon.2.What are you looking,Jim?3.You need a appointment if you want to see the dentist.4.I can wait 英语改错、、英语高手帮下忙 To my opinion,there are advantages and disadvantages traveling either by plane andby train.Travel by plane is time-saving ,comfortably,and you can have a good rest on the trip,but it is too expensive .Unless yo 形容看书快的成语 长2毫米的零件,把它按50:1的比例尺画在图纸上,应画多少厘米长帮个忙 给下面一段英语改错Today is monday,because sunday is overtime.so today is very tird.Today for me is pleasure,Mr.Gao called me yesterday night ,although only a little word,but for me,it is enough.For Mr.Gao,i think I love he.for his childish c 表现美好风光的成语至少三个 表现美好风光的成语有哪些 写出表现美好景色的成语 表现美好景色的成语非官方化工 谁能告诉我几个写表现美好风光的成语 在比例尺是5：1的图纸上,量得一种零件的长是2.5分米,这种零件的实际长度是（） 一个零件的长度是6.5毫米,画在一幅图上的长度是1.3分米,这幅图的比例尺是多少?