阅读下列材料，从每题所给的四个选项（A、B、C和D）中，选出最佳选项，并在答题卡上将选项涂黑。

    Even nowadays there are a lot of misunderstandings between nationalities. Let's have a look at what the following people have to say.

Maria Conti: I find the English people insincere (虚伪), cold and unfriendly. They keep saying "Thank you", "I'm sorry", even when they don't know each other. They are even polite to their own relatives! Except for helping you find your way in the streets, they aren't really friendly and never invite you to their houses.

Giannis Sinios: On the contrary I found them both broad-minded and friendly. I was invited to people's houses and they all showed great interest in my ideas, Greek life and people. In England I learned that it was possible to be warm, friendly and polite at the same time.

Judy Brown: I lived in both Italy and Greece for a few years. At first there were a few misunderstandings between my foreign friends and myself. For example, I once gave a Greek friend a present for her birthday. I was rather sorry that she didn't unwrap it immediately. What's more, she even didn't thank me until I asked her if she liked it! I've learned from different experiences that a lot of foreigners find our attitude to what we English people call politeness is rather insincere. They feel that politeness isn't necessary between friends.

 同学们整理实验室时，发现一瓶敞口放置且失去标签的白色粉末状药品，实验员老师告诉大家原瓶药品可能是碳酸钠、碳酸钙、氯化钠、氢氧化钠中的一种，同学们对此很好奇，于是他们对这瓶白色粉末的成分做了如下探究：

【实验Ⅰ】小明取一定量白色粉末于烧杯中，加水搅拌，充分溶解后，过滤，得到固体和无色溶液．

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.

在同一水平面上两次用测力计水平拉同一物体运动，两次运动的s﹣t图象如图所示，其对应的测力计示数分别为F₁和F₂，拉力功率分别为P₁和P₂，则它们大小正确的是（　　）

如图是对几种动物的相同点进行比较归纳（圆圈交叉部分为相同点），请据图回答下列问题