单选题

　　1.【阅读判断】Since 1939,numerous studies have been conducted to determine whether smoking is a health hazard. The trend of the evidence has been consistent and indicates that there is a serious health risk. Research teams have conducted studies that show beyond all reasonable doubt that tobacco smoking is associated with a shortened life expectancy.

　　Q：Smoking reduces one's life expectancy.

　　A.True

　　B.False

　　C.Not Given