正比例函数与反比例函数图象都经过点（1，4），在第一象限内正比例函数图象在反比例

（2011江苏连云港）某实验小组做“伏安法测量电阻”的实验，所用的器材有：电压为3V的电源，待测电阻R_x ，以及符合实验要求的滑动变阻器、电流表、电压表、导线和开关。图（甲）是没有连接完整的实物电路。

（1）请你用笔画线代替导线将实物电路连接完整。

（2）连接电路时，开关必须是＿＿＿＿，闭合开关前，应将滑动变阻器滑片P置于_________端（选填“最左”或“最右”）。滑动变阻器在本实验中的作用是                 。

（3）实验中，闭合开关，移动滑片．电流表、电压表均无示数。为了检查电路故障，他们借助一根检测导线进行检测，当该导线两端分别接不同点时．对应的现象如下表所示。由此可以判断电路发生的故障是________________________。

（4）排除故障后进行实验，当电压表示数为2.4V时电流表的示数如图（乙）所示，这时电流为_____A，他们利用此组数据即得出该待测电阻R_x的阻值，结束了实验。你认为他们这种做法有何不妥？答                       。

（5）第1小组测量的是小灯泡的电阻，第2小组测量的是定值电阻的电阻，两个小组都作出了I－U图像。你认为在图10中，属于第1小组的图像是     图，理由是        ；属于第2小组的图像的是＿＿＿＿图，理由是           。

慢性二尖瓣关闭不全最常见的病因是（）

A.二尖瓣脱垂

B.感染性心内膜炎

C.肥厚型心肌病

D.风湿性

E.先天畸形

阅读理解。

     A 69yearold grandmother with  no teeth of her own has eventually won a long legal  battle to stop a

Scottish regional council (政务委员会) adding fluoride (氟化物) chemical to the public water  supply.

     In a case which has already cost the taxpayer ￡1,000,000,the judge ruled that it was beyond the

powers of the local authority to add the chemical to the water in order to reduce tooth decay.

     At her home last night Mrs Catherine McColl said, "I did what I thought was right and I would do it

again, too." She claimed that adding fluoride to public drinking water made it into some kind of dirty

soup ."Where would it stop?"she asked. "They might come up with the idea of putting drugs into the

water to keep the unemployed quiet."It was a horrible poison, she said, that could have caused all kinds

of diseases, including cancer.

     The judge, however, concluded that there was no evidence  to suggest that the inclusion of fluoride in

the water supply would have had a negative effect on public health. Although the chemical might serve as

an efficient and convenient means of achieving a beneficial effect on  the dental health of consumers

generally, he said, and its  use was greatly favoured by the dental profession, he  could also understand

why some members of the public, Mrs McColl in particular, might be passionately opposed  to the

action of the Water Authority in assuming the  right to improve public wellbeing without consulting the

public in the first case. The Authority's legal duty to provide "wholesome" water for public consumption

which was both safe and pleasant to drink ,did not,he said, extend to their right to safeguard public health

by chemical means.

1. Mrs McColl felt so strongly about the fluoride issue that she eventually ________.

A. took the local council to court

B. had a physical fight with the judge

C. urged the authority to apologize

D. spent much money removing the chemical

2. According to what the judge said in the passage, adding fluoride to the water________.

A. was not proved to be harmful

B. was the duty of the local authority

C. was strongly opposed by dentists

D. was surely beneficial to the public

3.The word "wholesome"in the last paragraph can be best replaced by the word"________".

A. clear    

B. poisonless

C. healthy   

D. recycled

4. From the passage we learn that people like Mrs McColl are more concerned about________.

A. the improvement of their personal health

B. the problem of unemployment in their community

C. the chemicals to be used for the improvement of water quality

D. their right to be informed of the authorities' decisions

水生生态系统的食物链一般比陆地生态系统的食物链长。( )

总配电箱应设在靠近电源的区域，分配电箱应设在用电设备或负荷相对集中的区域，分配电箱与开关箱的距离不得超过（）m，开关箱与其控制的固定式用电设备的水平距离不宜超过3m。

A、30

B、40

C、50

D、60