4-1试求题4-1图所示电路中电容上电荷量的初始值以及电容上电荷量在t=0.02s时的值。设换路前电 路工作了很长的时间。 4-2在工作了很长时间的题4-2图所示电路中开关S1和S2同时开、闭,以切断电源并接入放电电 阻R。试选择R的阻值,以期同时满足下列要求:

1-1求题1-1图各分图中的待求电压、电流值(设电流表内阻为零)

人们在实践的基础上形成了许许多多的反映事物本质属性的概念,并运用这些概念去 反映客观事物。但是逻辑并不去关注这些概念是如何反映客观事物的,它只把它作为形式 抽去出来,把表达了不同概念的同一语词作为研究对象。同样,人们常常不是单纯地运用 孤立的概念进行推理,而是通过概念组成的命题进行思维和交流的

Teaching Outline Pre-reading Questions Background Information Passage AnalySIs style and structure spelling word derivation language points useful expressions

Background information Croydon city in the south east of England Victorian house Sash-window General School Certificate

Text I Christmas What do you know about Christmas? Christmas Christmas tree Christmas card Christmas books Nicholas SAINT

General Organization Comprehension Language points Interaction activity

Introduction Although the world is large, man is able to live in only a small part of it. The atmosphere is only about eleven kilometers thick. The soil that supplies us with food is only about fifteen centimeters thick and man can live on only about one eighth of the world's surface. In the past two hundred years man has greatly changed his environment. Water has been given to deserts. Roads have been built across deserts and through forests

霉形体培养特性 一、营养要求比一般细菌高,除基础营养物质外还 需加入10~20%人或动物血清以提供支原体所 需的胆固醇。大多数兼性厌氧,有些菌株在初 分离时加入5%CO生长更好

一、掌握PLC工作原理、结构特点。 二、熟悉基本逻辑指令、顺序控制指令及常用的功能指令。 三、具备PLC应用系统设计初步能力