Different countries have different customs. When you travel to another countries，please follow their customs，just as the saying goes，“             .”Very often people who travel to the United States forget to tip（付小费）.It is usual to tip porters who help carry your bags，taxi drivers and waiters. Waiters expect to get a 15% tip on the cost of your meal. Taxi drivers expect about the same amount.
In England，make sure to stand in line even if there are only two of you. It's important to respect lines there. It’s a good idea to talk about the weather. It's a favorite subject of conversation with the British.
   In Spain，it's a good idea to have a light meal in the afternoon if someone invites you for dinner. People have dinner very late，and restaurants do not generally open until after 9 pm.
   In Arab countries，men kiss one another on the cheek（脸颊）. Your host may welcome you with a kiss on both cheeks. It is polite for you to do the same.
   In Japan，people usually give personal or business cards to each other when they meet for the first time. When a person gives you a card，don't put it into your pocket right away. The person expects you to read it.Don't forget to be careful of your body language to express something In conversation. A kind of body language that is acceptable in one culture may be impolite in another.

$\sqrt{3}$的倒数是（　　）

现有甲、乙、丙、丁四种金属，将它们分别投人盐酸中，只有丙、丁发生反应并产生气泡；将丁投入丙的硝酸盐溶液中，有金属丙析出，将甲投入乙的硝酸盐溶液中，有金属乙析出．这四种金属的活动性顺序是（   ）

我国全面推进依法治国的总目标是（    ）

我市某一周的每一天的最高气温统计如下表：

则这组数据的中位数是____，众数是____．