.4极限存在准则与两个重要极限 本节先介绍极限存在准则利用它们来导出两个重要极限. 一、极限存在准则 准则I(夹逼定理)若Vx∈U(x,)(或|x>M),均有g(x)≤f(x)≤h(x)且limg(x)=limh(x)=A,则有limf(x)=A

Part I Reading Comprehension (40%) Task 1 Directions: Choose the best answer from the 4 choices Air pollution can spread from city to city. It even spreads from one country to another. Some northern European countries have had\black snow\ from pollutants that have traveled through the air from other countries and have fallen

Part I Multiple Choice (15%) 1. He 1978 we have lost ct with each other so ar C) ever since B)to go ever so

Part I Multiple Choice (15%) 1. He a good student A)am C)are B)is D)W

Part I(25%) Directions: This part is to test your ability to construct grammatically correct sentences. It consists of 2 sections Section A Direction: In this section, there are15 incomplete. You are required to complete each one by deciding on the most appropriate words from the four choices

Part I Reading(40%) Every human being, no matter what he is doing, gives off body heat. The usual problem is how to dispose of it. but the designers of the Johnstown Campus of the University o Pittsburgh set themselves the opposite problem how to collect body heat. They have designed a collection system which utilizes not only body heat, but the heat given off by such

Part I Structure(30%) Directions: In this section, there are 20 incomplete sentences. You are required to complete each one by deciding on the most appropriate word or words from the 4 choices marked A), B), C and D). Then you should mark the corresponding letter on the Answer Sheet with the size of the whole earth, the highest mountain does not seem high at all

Part I Reading(40%) Passage 1 Malcolm Greenway is thirty-five years old, married with two children. He lives in a town about twenty kilometers away from the school in which he teaches, and goes to work every morning by car. The village school was built about forty years ago by the local education authority for only about sixty. a new room has recently been added to be used as a dining room, and the playground has been enlarged and improved. A woman teacher is in charge of the youngest children

Part I Vocabulary Structure(20%) Section a employee C. calculator D. device

FET的小信号等效模型电路十分简单,由于栅源之间的输入 阻抗很高,无输入电流,故呈开路状态。其漏源之间在恒流区 工作时,也是一个正向受控电流源,输出受Gs控制,为表 示uGs对i的控制能力,通常来表示