If it is quite _________to you, I will v

如下图所示，光滑水平桌面上有长L＝2 m的挡板C，质量m_C＝5 kg，在其正中央并排放着两个小滑块A和B，m_A＝1 kg，m_B＝3 kg，开始时三个物体都静止。在A、B间放有少量塑胶炸药，爆炸后A以6 m/s速度水平向左运动，A、B中任意一块与挡板C碰撞后，都粘在一起，不计摩擦和碰撞时间，求：

①当两滑块A、B都与挡板C碰撞后，C的速度是多大？

②A、C碰撞过程中损失的机械能。

外斐反应属于

A．直接凝集反应
B．沉淀反应
C．间接凝集反应
D．协同凝集反应
E．反向凝集反应

D

Our 16-year-old daughter started to smoke last Christmas. It killed me to see that lovely girl with a cigarette(香烟) in her mouth. I told her how I felt. Martha continued to smoke（抽烟）, saying, “It's my life,” and so on. I told her if she didn't stop smoking, I wouldn't send her to college. She agreed to give it up.

Last night there was cigarette smell on Martha's breath(呼吸). She had to say she had broken her word. Now I must do what I've said to punish(惩罚) her.

Martha is unusually bright and wants to teach children. I'm working full-time to put her older sister through school and would do the same for Martha. My husband's pay is good, but with prices going up all the time we could never educate the girls unless I kept on working.

My theory(理论) is that if smoking is more important to Martha than college, I'm a fool to work to put her through college.

68. Why did the mother feel sad?

A. Because her daughter failed to go to college.

B. Because her daughter tried to kill her.

C. Because her daughter promised to smoke no more.

D. Because her daughter got used to smoking.

79. The mother warned that if Martha didn't give up smoking, she would ______.

A. refuse to give Martha any money

B. not be Martha's mother

C. refuse to pay for Martha's college education

D. not let Martha teach children

70. What did Martha really do after mother warned her?

A. She failed to keep her promise.

B. She kept her promise.

C. She managed to give up smoking.

D. he broke something her mother give her.

校长的成长与发展

根据《中华人民共和国循环经济促进法》，设区的( )循环经济发展综合管理部门会同本级人民政府环境保护等有关主管部门编制本行政区域循环经济发展规划，报本级人民政府批准后公布施行。

A．乡镇以上地方人民政府
B．县级以上地方人民政府
C．市级以上地方人民政府
D．省级地方人民政府