通过圆水准器球面中点的铅垂线称为圆水准轴线。（）

如图所示，电源电压恒定不变，电阻R₁的阻值为20Ω，滑动变阻器的最大阻值R₂为40Ω，小灯泡的额定电压为18V，灯丝电阻不随温度发生变化，闭合开关S.当开关S₁、S₂都断开时，滑动变阻器的滑片P移动到中点时，电流表的读数为0.3A；当开关S₁、S₂都闭合时，滑动变阻器的滑片P移动到最右端时，电流表的示数为0.9A，求

（1）电源电压是多少？

（2）当开关S₁、S₂都断开时，通电1min，电路中产生的最大热量是多少？

（3）当开关S₁、S₂都闭合时，滑动变阻器的滑片P移动到最右端时，请你分析这是一个什么电路，并画出该电路的最简化电路图.

（4）小灯泡的额定电功率是多少？

甲上市公司(以下简称甲公司)经批准于20×1年1月1日以50400万元的价格(不考虑相关税费)发行面值总额为50 000万元的可转换债券。 该可转换债券期限为5年，票面年利率为3%。自20×2年起，每年1月1日付息。自 20×2年1月1日起，该可转换债券持有人可以申请按债券面值转为甲公司的普通股(每股面值1元)，初始转换价格为每股10元，不足转为1股的部分以现金结清。

其他相关资料如下：

(1) 20×1年1月1日，甲公司收到发行价款50 400万元，所筹资金用于某机器设备的技术改造项目。该技术改造项目于20×1年12月31日达到预定可使用状态并交付使用。

(2) 20×2年1月1日，该可转换债券的50%转为甲公司的普通股，相关手续已于当日办妥；未转为甲公司普通股的可转换债券持有至到期，其本金及最后一期利息一次结清。

假定：

①甲公司对债券的溢价采用直线法摊销；

②每年年末计提债券利息和摊销溢价；

③20×1年该可转换债券借款费用的80%计入该技术改造项目成本；

④不考虑其他相关因素。

要求：

编制甲公司20×1年12月31日计提可转换债券利息和摊销溢价的会计分录。

现在家家户户都安装了漏电保护器，有人认为它与保险丝的作用一样，用电器电流大时，它自动跳闸，起到保险丝的作用，只是不熔断。其实不是这样，它的作用与保险丝的作用完全不一样，它是只管漏电(跑电，与大地相连)而不管短路，当然，当电流大到某一极限值时它也跳闸。漏电保护器是保护人的生命安全的，一旦有人触电，它会立即跳闸，切断电源。它的原理图如图所示。当用电器一端有人触电(或漏电)时，套在闭合铁芯上的线圈就向传感器发出信号，通过自动电路，切断电源。试说明漏电保护器的原理。

阅读理解。

     The pupils of the remote Beau-Roc primary school in Haiti are chanting (singing the same words again

and again). One of them plays a guitar made from an empty oil tin. Their headmistress, Emile Jean-Noel,

is one of the few women school headteachers in the country.

     Today, over 70% of Haitian population live without proper food, water, schools, or housing. To reduce

the hunger that prevents learning and to encourage parents to send their children to school, meals are

provided by the World Food Programme.

     "We are so cut off that we have many difficulties," comments Emile, adding that finding chalk, school

books and other materials is practically impossible. Emile tries to encourage people around her to make use

of available resources. Her efforts are bearing fruit. One of her successes was convincing local women to

contribute to their children' s schooling and increase their income by selling embroidery ( 刺绣) and other

handicrafts.

     Recent political instability (不稳定) has meant that the country has not invested (投资) in education for

ten years. Only 44% of children go to school and less than half of them finish primary school.  Less than a

third of these children go on to secondary school. In rural areas it is not rare to find 17 and 18 year olds in

primary school- Beau-Roc has only 4 teachers for 260 pupils. Emile works constantly to improve her pupils'

environment. Under her direction, a local worker is now constructing a store house for the food delivered

regularly by the WFP.

     Not only is Emile' s salary small, but she receives it irregularly. For her, transport is a real headache. She

lives five kilometers away and has to take the tap tap, a privately-owned bus, costing more than she can

afford. 

     "The decision to be a rural teacher in Haiti should not be taken lightly", Emile comments. "With all the

sacrifices and risks it requires, only those who are really cut out for teaching should do it." However, Emile

loves her job. "I always feel at home with the children and, because the parents understand what I'm doing,

I try to give my best."

1. Which of the following is extremely difficult for Beau-Roc primary school?

A. Teaching the women how to make embroidery and other handicrafts.

B. Persuading local women to care about their children' s education.

C. Encouraging people around to use those available resources.

D. Finding chalk, school books and other materials.

2. In the last paragraph, "those who are really cut out for teaching" refer to people who are _____.

A. dismissed from teaching

B. unfamiliar with teaching

C. qualified for teaching

D. cautious about teaching

3. What topic is presented in this passage?

A. Hardship for teachers.

B. Devotion to education.

C. Politics and children.

D. Love and beauty.

简述陈列设备摆放的工作要求。