单选题 Smoking is considered dangerous to the health. Our tobacco-seller, Mr. Smith, therefore, always asked his customers, if they are very young, whom the cigarettes are bought 1 .
One day, a little girl whom he had never seen before walked 2 into his shop and demanded 20 cigarettes. She had the 3 amount of money in her hand and seemed very 4 of herself. Mr. Smith was so 5 by her confident manner that he 6 to ask this usual question. 7 , he asked her what kind of cigarettes she wanted. The girl replied 8 and handed him the money. While he was giving her the 9 , Mr. Smith said laughingly that 10 she was so young she should 11 the packet in her pocket in 12 a policeman saw it. 13 , the little girl did not seem to find this funny. Without 14 smiling she took the 15 and walked towards the door. Suddenly she stopped, turned 16 , and looked steadily at Mr. Smith 17 was a moment of silence and Mr. Smith 18 what she was going to say. All at once, in a clear 19 voice, the girl declared, " 20 dad is a policeman," and with that she walked quickly out of the shop.