2.“a=2”是“直线ax+2y=0与直线x+y=1平行”的

　 (A)充分不必要条件　　　　　　　　　 (B)必要不充分条件

　 (C)充要条件　　　　　　　　　　　　 (D)既不充分也不必要条件

1.若

　 (A)　　　　　　　 (B)

　 (C)　　　　　　　 (D)

听力录音稿

Text1

W: What jobs have you done in the past five years?

M: All right. I was once a waiter and later a businessman. Up till now, I’ve been driving buses for two years.

Text2

W: Have you heard people talking about stand by you these days?

M: Oh, yeah. There are some beautiful songs in the collection and they really remind me of my first love.

Text3

W: Don’t forget to write to me, Jason.

M: I won’t. But let me make sure I have the right address. Is it 42 East Drive, Birmingham?

W: That’s right. By the way, my office number has changed since I began to work at Morrison Company.

M: Has it? Then, please tell me what it is.

Text4

W: Oh, there you are! Glad to see you again! Did you have a good flight?

M: Sure, I flew all the way direct from Seattle to London.

W: You must be very tired. Did you sleep at all on the plane?

M: No, not really. Sorry, could I use your bathroom now?

Text5

M: Hi, Susan Can you help me decide what to buy for Peter’s birthday?

W: Maybe you could give him the new Ricky Martin CD.

M: Ricky Martin? That’s not the rock music. Peter wouldn’t like that.

W: How about a Rolling Stone CD?

M: Sounds a good idea.

Text6

W: Are you having any problem, sir?

M: Yes. I need a major book for my history research paper and I’ve tried the card list, but it’s not there.

W: Well, if it’s a recent book, it won’t be in the card list. All the information about books since 1995 is in the computer. I’d advise you to try it.

M: No wonder! This book was punished in 1998.

W: All you have to do is to type in the title or the writer’s name.

M: Do you mean it will also give you the due date. If the book is in the library, it will tell you where you can find the book.

Text7

W; We are thinking about putting on a show this spring.

M: Do you think you’ll be able to make some money?

W: Oh, no. we just want to do it for having fun.

M: What kind of show are you going to put on?

W: A musical play.

M: Have you decided which ones to do it?

W: We have three in mind, and of course. We’ve been thinking about you.

M: Me?

W: Yeah, everyone says you have a beautiful voice.

M: But everyone knows I’ve never appeared on a stage.

W: But you sing in church every Sunday, right?

M: Yes, but it’s different, you know.

W: Come on. Here’s the chance to find out how great you are. Not just to sing, but to act and dance, too.

M: Ok, it might be exciting.

Text8

W: Tom, do you mean you’re going away?

M: Yes, I’ve booked the ticket. And it’s time for me to go back to Australia.

W: How long have you been in Chengdu?

M: Since I graduated from Sichuan University in 2003.

W: Did you enjoy your stay here?

M: yes, indeed. This city is really a paradise for people to live in. You have given me a lot of help. All people here are very friendly to me in the past years. Thank you all very much.

W: When are you leaving?

M: I’m off next Monday. I’ve come to say goodbye today.

W: Id like to invite you to my home for dinner before you go. What about Saturday?

M: I’d love to. But I’ve promised Mr. Zhang Ping to have a hotpot on Saturday. Well, how about joining us, then? You’ve met Mr. Zhang Ping before, who works in the ticket office.

W: That would be fine. Do you mind if I take my husband and my daughter together with me?

M: Not at all. All your family are welcome.

Text9

W: Why don’t we go abroad for a change, Simon? Where I’d like to go is France, Spain, or Italy.

M: Mm……I’m not that interested at all. I’d rather stay at home.

W: Oh, come on, Simon. Think of the sun!

M: Yes, but think of the cost! The best thing about having a holiday in Britain is its cheaper expense. And another thing, the traveling would be easier. No boats, planes or anything.

W: Even so, we’ve been to most of the interesting places in Britain. There’s no point in wasting our summer holiday here.

M; I suppose you’re right. However, What I hate is the trouble in changing money abroad.

W: Oh, don’t be silly, Simon.

M: And what’s more, I can’t speak any of the languages, you know that. It’s all right for you. You can speak foreign languages.

W: Exactly. You see, what I’d really like to do is to practice my French and Spanish. It would help me a lot at work.

M: But that’s no use to me.

W: But think of the new places we would visit and the people we would meet.

M: But, look, if we stayed here, we wouldn’t have to plan very much.

W: Sorry, Simon., I just don’t want to have another boring English summer here.

Text10

The train I was traveling on was half an hour late. I had planned to arrive in Kunming in time to catch the 11:35 train to Dalian. There would be three quarters left for me according to the timetable----but there was no hope for it now. I explained the situation to the conductor, who told me to get off at the stop before Fangshan Station and take a taxi. When the time came, he even helped me with my luggage. He wished me good luck as I jumped off, and a few minutes later I was racing towards Fangshan Station in a taxi. It was almost 11:35 when we stopped outside the station. I paid the driver quickly, grabbed my bags and hurried inside.

“The train…..?” was all I had time to say to the first porter I saw. You can imagine my disappointment when he pointed to the train that was just pulling out of the station.

36、如图所示利用小型发电机给工厂中的电动机和灯泡供电，发电机的输出功率为1KW，输电电压为250V，发电机与工厂之间距离为为400m，发电机与工厂之间两根输电导线总电阻为7.5Ω，其它导线电阻忽略不计，在该电路中灯泡的实际功率为110W，电动机线圈电阻4Ω。试求：

(1)输电效率为多少？

(2)电动机的电功率以及输出功率。

35、有一种“压力测量仪”，其测量部分的原理如图所示，由压敏电阻R(电阻值随所受压力变化而变化)、数字式仪表P(电阻可忽略不计)、滑动变阻器、电池等组成电路。压敏电阻R在一定范围内的电阻与所受压力的关系如下表所示，R₀为滑动变阻器用作仪表P的调零。台板部分的质量忽略不计，电源电压为12V。

(1)在图乙坐标中作出压敏电阻的电阻值与压力的关系图线。

(2)由图线求压敏电阻为192Ω时，所受的压力是多大?

(3)台板上无物体，仪表P示数为零时R₀为100Ω，电路中的电流是多大?由于某种测量需要，在台板上放置一块重250N的垫板，调整R₀使仪表P示数为零，求此时调零电阻R₀消耗的功率。

34、图甲和图乙是利用热敏电阻来测量温度的原理图。电源电压均为20V且保持不变，定值电阻R₀的阻值为30Ω．则：

　(1)图甲中电流表的示数为0．3A时，热敏电阻两端的电压和消耗的功率分别是多少？

(2)图乙中电压表的量程为0-15V，热敏电阻R的阻值随温度的变化关系如图丙所示，试求此电路能测量的最高温度．

33、在探究“影响电磁铁磁性强弱的因素”实验中，小明用相同的漆包线和铁钉绕制成电磁铁A和B，设计了如图所示的电路。

(1)实验中是通过电磁铁　　　 ________________来判定其磁性强弱的，所使用的物理研究方法是　　　　　　　　　 。

(2)图中A、B串联的目的是_________　　 _。

(3)闭合开关后，分析图中的现象，得出的结是　　　　　　　　　　　　　　 。

(4)B铁钉的钉尖是________极。若让B铁钉再多吸一些大头针，滑动变阻器的滑片应向______端移动。(选填“左”或“右”)

32、是某课外活动小组仿制的一个能产生持续电流的装置-发电机，装有手摇柄(未画出)的转轴垂直穿过圆盘中心，金属圆盘放在蹄形磁铁之间，圆盘的轴心和能在圆盘的边缘滑动接触的滑片通过金属导线与电流表相连。金属圆盘可以看成是由无数根长度等于圆盘半径的导线组成的，圆盘在磁极间不断转动，每根导线都在做切割磁力线的运动，从而产生持续电流。当以某一转速匀速转动金属圆盘时，电流表有一定的计数。根据上述材料，请完成下面的实验探究填空：

　　 (1)换用　　　　　 的磁铁，其它条件不变，发现电流表读数增大，说明电流大小跟磁场强弱有关； 　　 (2)换用一个半径大一些的金属圆盘，其它条件不变，发现电流表读数增大，说明电流大小也跟　　　　 有关； 　　 (3)当圆盘转速增大，其它条件不变时，发现电流表读数也增大，说明电流大小还跟　　　　 有关。

31、小雨在拆装手电筒时，发现手电筒的小灯泡上标有“3．8V”的字样，但上面的电流值已经模糊不清，他想通过实验测量该灯泡的额定功率，下图为他所连的实验电路．

(1)电池盒中至少有__________节干电池。

(2)经检查发现电路接线有错误，小雨只做了一处改动就闭合开关进行实验，请在他接错的导线上打上“×”，并改正，要求滑动变阻器的滑片向左移动时灯泡变亮。(1分)

(3)实验时，小雨移动滑动变阻器的滑片，当电压表的示数为3．8V时，电流表的示数如图乙所示．则该小灯泡的额定电流为_________A，额定功率为_________W．

(4)若小雨的同学在电池盒中装入了4节干电池，原本打算使用小雨的实验方案，来测量一个标有3.6V，估计额定功率为0.9W的小灯泡，当他闭合开关，发现电压表0-15V量程不灵，无法按照常规方法进行试验，请在不增减器材的的情况下，重新设计出测量小灯泡额定功率的的电路图，请画在右上方。(1分)

(5)若实验室里边有四种规格的滑动变阻器：“9Ω，1A”，“15Ω，1A”，“12Ω，1A”，“20Ω，1A”，则无论是按照小雨设计的方案还是小雨同学更改的实验方案，都应该选用　　　　　　 规格的滑动变阻器为宜。

30、将如图所示电水壶的三条接线按照安全用电的原则对应连接到插头上。