轴和轴套的磨损按磨损形式分类（）。A.均匀磨损 B.单向载荷引起的磨损 C.双向反复

Love Is the Band-Aid(创可贴)

“What are you busy with yourself，Mom?”the girl of six years old asked her mother.

“M        dinner for the neighbor aunt.”    “Why?” 

“Because the other day the aunt lost her dear daughter in the earthquake and is s _______ sad now. We must take

g          care of her these days.”

“W          need our care?”

“Because from then on the aunt can’t do what she liked to along with her daughter. Making dinner and doing housework are also becoming so d         . I don’t know what to do. My dear, can you come up with an idea to make the aunt feel b         ?”

All of a sudden，the girl went to the neighbor’s house and k           at the door.

“What can I do for you?” asked the neighbor.   

“I heard my mother say you’re very sad w         your daughter…..”The girl handed the band-aid tightly held in her hand to the neighbor.

Tears ran down from the neighbor’s eyes. She took the girl in her a          and said，“Thank you. Your band-aid will h         .

关于做“测电源电动势和内电阻”的实验。

（1）有同学按图（a）电路进行连接，他用到的6根导线是aa′、bb′、cc′、dd′、d′e和bf ，由于其中混进了一根内部断开的导线，所以当他按下开关后，发现两个电表的指针均不偏转，他用多用表的电压档测量bc′间的电压，读数约为1.5V（已知电池电动势约为1.5V），根据上述现象可推得，这6根导线中可能哪几根内部是断开的？答：_____________（写导线编号）。为了确定哪一根导线的内部是断开的，他至少还要用多用表的电压档再测量几次？答：______________次。

（2）排除故障后，该同学通过改变滑动变阻的电阻，测得了6组U、I的数据，根据第1、2、3、4、5和6组的数据，他在U-I图上标出了这些数据点，并且按照这些数据点的分布绘制了相应的U-I图线（如图（b）所示），由这一图线，可求得电源的电动势E为________V，内电阻r为________Ω。如果他不利用这一图线，而是利用任意两组U、I数据，那么当他选择哪二组数据时求出的E、r值误差最大？答：________________（写数据组编号） 。

(14分)理想变压器原线圈中输入电压U₁＝3300 V，副线圈两端电压U₂为220 V，输出端连有完全相同的两个灯泡L₁和L₂，绕过铁芯的导线所接的电压表V的示数U＝2 V．求：

(1)原线圈n₁等于多少匝？

(2)当开关S断开时，电流表A₂的示数I₂＝5 A．则电流表A₁的示数I₁为多少？

(3)当开关S闭合时，电流表A₁的示数I₁′等于多少？

处于冰山模式图最顶端的是人的应对方式。

或有负债比率是或有负债与所有者权益之比，该指标越高，反映企业承担的风险越大。 ( )