赵某等3名大学生通过招聘与市环卫处签定劳动合同，成为垃圾清运工。他们说，做清运工是凭个人本事挣钱，没什么丢人的。这给我们的启示是（  ）

①要树立正确的职业观念                                                       ②要正确对待理想与现实

③在升学和就业面前，要从实际出发，做出理性选择       ④在艰苦的环境中锻炼自己，理想就能实现

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.