Social customs and ways of behaving change from time to time. Things which were considered impolite many years ago are now acceptable. Just a few years ago, it was considered impolite for a man to smoke on the street. No man who thought of himself as being a gentle—man would make a fool of himself by smoking in the presence of a lady. Customs also differ greatly from country to country. Does a man walk on the left or the right of a woman in your country? Should you use both hands when you are eating? (76) The Americans and the British not only speak the same language but also share a large number of social customs. For instance, in both countries, people shake hands when they meet each other for the first time. Also, most Englishmen will open a door for a woman or offer their seat to her, and also will most Americans. Promptness (守时) is important both in Britain and America. If a dinner invitation is for 7 o'clock , the dinner guest either arrives close to that time or calls up to explain his delay. The important thing to remember about social customs is not to do anything that might make other people uncomfortable. Especially if they are your guests. There is an old story about a man who gave a formal dinner party. When the food was served, one of the guests started to eat his peas with a knife. The other guests were either amazed or shocked, but the host calmly picked up his knife and began eating in the same way. It would have been bad manners to make his guest feel foolish or uncomfortable. If a dinner guest is to be late for dinner, he should ______.