阅读下列短文,从每小题所给的A、B、C三个选项中选出一个最佳选项。

    People don't mind if you put your elbows or arms on the table when you are not eating. But once you have started eating, you should only rest your forearms(前臂) on the table. You should let your kids know that table manners are more than about proper eating. Teaching your kids the following table manners whether they are eating in a restaurant or at home:

◆You should use a fork unless the food is meant to be eaten with fingers.

◆You should not fill your mouth with food.

◆You should chew with your mouth closed. Nobody likes to see food being chewed up or hear it being chewed on. You should not talk while your mouths full of food.

◆If you want something that is out of your reach, then just ask someone to pass it on to you.

◆You should not pick anything out of your teeth. If something is troubling you very much, you can excuse yourself and go to the restroom to pick it out.

◆You should always use a napkin to wipe your mouth, which should be placed on your lap when you are not using it. You shouldn't wipe your face or your nose with a napkin, both are unpleasant.

◆If you are eating at someone's home, don't forget to express(表达) your thanks to the host. Also, tell him how delicious the food is, even if it isn't.

将一定量的Cl₂通入一定浓度的苛性钾溶液中，两者恰好完全反应(已知反应过程放热)，生成物中有三种含氯元素的离子，其中ClO^－和ClO₃^－两种离子的物质的量（n）与反应时间（t）的变化示意图如右图所示。下列说法正确的是

干簧管是一种利用磁场来工作的开关器件，也叫磁控开关．常用的干簧管有单触点和双触点两种．双触点干簧管类似于单刀双掷开关，它的工作原理是：没有磁场时，簧片1与簧片2接通（如图甲），当有外界磁场时，簧片1与簧片2的连接断开，簧片1与簧片3触点部位接通（如图乙），其中簧片1是公共端，簧片2是常闭接点，簧片3是常开接点．簧片中有一片是用只导电不导磁的材料做成．

如图，塔吊臂上有一可以沿水平方向运动的小车A，小车下装有吊着物体B的吊钩，在小车A与物体B以相同的水平速度沿吊臂方向匀速运动的同时，吊钩将物体B向上吊起，A、B之间的距离以d=H﹣2t²（SI）（SI表示国际单位制，式中H为吊臂离地面的高度）规律变化，则物体做（   ）

下图中左边的飞机通过平移可以与下面的（  ）号飞机重合。