47、Which of the following is fairly common among young smokers ?

　　A.Laziness.

　　B.Lack of confidence.

　　C.Ignorance.

　　D.Disobedience.

　　48、Which of the following is NOT true according to the passage ?

　　A.To prevent children from start smoking，parents，teachers and health care workers should not smoke.

　　B.It's easier to prevent children from starting to smoke than to persuade adults to stop smoking.

　　C.Many children start to smoke because they want to appear mature.

　　D.Some children start to smoke merely out of curiosity.

　　49、The author concludes that school rules to forbid smoking__________ .

　　A.should be introduced although it might prove ineffective

　　B.should be introduced because it was done at the school he studied

　　C.should not be introdticed because it may cause rebellion

　　D.needn’t be introduced as long as the teachers don’t smoke

　　50、Which is the author's attitude towards children smoking?

　　A.Indifferent.

　　B.Sympathetic.

　　C.Fmntional.

　　D.Obieetive.