单选题 Smoking is very prevalent (普遍的) in the West, both by men and by women. But there are still people who do not smoke and who dislike the smoke of others. Be careful not to smoke in such a way or in such a position that your smoke blows into others faces. If you are a guest in a home where no others are smoking, it is better to refrain from smoking. If you think they would not mind your smoking, you may say, "Would you mind if I smoked?" and await their assurance (承诺) before lighting up. There are many places where people do not or should not smoke: public meetings, movies and plays, stores, ball-rooms, trains (except in the smoking car), buses (except in the back seats), at the dinner table (except when invited by the hostess near the end of the meal to do so). Many people feel that ladies should not smoke on the street.
Be a clean smoker—use an ash receiver and put out the cigarette completely when you are finished. Be very careful where you put down your lighted cigarette; it is thoughtless and inconsiderate to allow your cigarette to bum the furniture or table covers.

单选题 What does the sentence "... it is better to refrain from smoking" mean?

单选题 If you are in another person"s home and want to smoke, what should you do?

单选题 People shouldn"t smoke unless ______.

单选题 What does the writer suggest people do when they finish smoking?