现有两枚质地均匀的正方体骰子，每枚骰子的六个面上都分别标有数字1、2、3、4、5、6．同时投掷这两枚骰子，以朝上一面所标的数字为掷得的结果，那么所得结果之和为9的概率是（   ）

    One afternoon last week, I saw three tearful children from my son's school being comforted by teachers. That morning, my 11-year-old had stomach pains, retching(干呕)into a bowl. Talking to other mothers later, I heard about other children with stomachache or difficulty sleeping the night before.

What caused so much pain? Sports day. Sports day might be necessary at a highly-competitive independent school, but not at a village primary school. For the children who can fly like the wind, sports day causes no problem. For those who are overweight or just not good at sport, it is a nightmare(噩梦). Even for those who enjoy running but fall halfway down the track in front of the entire school and their parents, it can prove a disaster.

    Why do we put our children through this annual suffering? Some may say competition is character building; or it's taking part, not winning, that's important; or that it is a tradition of school life. I just felt great pity for those children in tears or in pain.

    Team games at the end of sports day produced some close races, wild enthusiasm, lots of shouting—and were fun to watch. More importantly, the children who were not so fast or quick at passing the ball were hidden a little from everyone's eyes. Some of them also had the thrill of being on the winning side.

    I wish that sports day could be abandoned and replaced with some other less-competitive event. Perhaps an afternoon of team games, with a few races for those who want them, would be less stressful for the children and a lot more fun to watch.

根据下列装置图回答问题（装置图用符号表示）

（1）写出编号①②的仪器名称：①____②____

（2）双氧水（H₂O₂）是无色液体，可发生如下化学反应：2H₂O₂$\stackrel{Mn{O}_2}{=}$2H₂O+O₂↑，在实验室利用此反应制取氧气时，应选用的气体发生装置是：____ ．

（3）实验室用大理石和盐酸反应制取二氧化碳，在生成的气体中混有少量氯化氢和水蒸气．C装置可用于除掉水蒸气，可选用____ 作干燥剂（填名称）．根据下列各备选试剂的性质，利用D装置除掉氯化氢时，应选择的最佳试剂是：____ （填序号）①饱和石灰水  ②氢氧化钠溶液  ③碳酸钠溶液  ④饱和碳酸氢钠溶液

2NaOH+CO₂═Na₂CO₃+H₂O　　　　　　Na₂CO₃+H₂O+CO₂═2NaHCO₃

Na₂CO₃+2HCl═2NaCl+H₂O+CO₂↑　  NaHCO₃+HCl═NaCl+H₂O+CO₂↑

（4）将制取二氧化碳的装置按发生、净化和收集的顺序进行连接，装置依次为____ 　（填装置序号）

一瓶可乐原来5元，节日一律打八折，现每瓶售价____元。