题目

Different countries have different customs. When you travel to another country, 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 5．根据图原子结构示意图填空：该元素的元素符号为：Cl．在化学中反应中它的原子易得到电子，变成阴（阴或阳）离子，其离子符号为Cl-．