Different from popular thoughts, sometimes flu（流感） is not caused by bad weather. It is caused by viruses in the body.  51 ,  A/H1N1 flu has been spreading in the most parts in the world. Some studies have now shown that one of  52 ways of spreading the viruses is through the air when  53 A/H1N1 flu-sufferer coughs or sneezes. However, its viruses can sometimes spread by  54 . After a flu-sufferer rubs his nose, the viruses might be spread to his hand. Then a friend 55 to visit him, they shake their hands. The friend then gets something  56  by hand, and several days  57, he is infected. A child  58  is carrying A/H1N1 viruses uses tissues（面纸） to clean his running nose, although his parents pick up the tissues and carefully throw  59 away, they fail to wash their hands, and they will catch the viruses, too. So it is important for you to wash your hands often, it will stop the viruses from  60 in a way.

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.
【小题1】When you travel to the USA，you don’t need to tip           .