[单选题]除设有人员密集场所以外的其他建筑的封闭楼梯间或防烟楼梯间的门的损坏率超过其设置总数的( )可作为重大火灾隐患综合判定要素之一。[易]
A.30%
B.40%
C.50%
D.60%

王教授在2003年6月完成一本学术专著并于同年12月由出版社出版。这部学术专著是王教授单位的一项科研课题，单位为王教授的写作与研究提供了便利条件，但王教授与单位没有就专著的著作权属进行任何约定。王教授的同事甲为了使王教授能顺利完成该学术著作，承担了王教授其他课题的组织工作，为其创造了良好的研究条件。专著出版后，另一所大学的乙教授对该专著非常推崇，不仅将其作为研究生教学的指定教材，而且在自己的研究成果中引用了王教授著作的若干结论，并且都注明了出处。
根据上述事实和著作权法律制度的规定，回答下列问题：

According to the USA Office on Smoking and Health, more than 3,000 children become smokers every day. 63 percent of all American high school seniors have tried smoking. Nearly one in five smokes daily.
It is apparent that no matter how many times children are told, a great number of them are going to try smoking anyway. Peer pressure plays an important part. Many children start smoking because their friends have tried it. Smoking may get them in with the "in crowd" and help them to make friends. If they smoke, they will be accepted by their peers.
How to avoid the child to be one of the smokers is a severe problem for the whole society. According to the Department of Health and Human Services, 11 percent of boys and 8.5 percent of girls smoke their first cigarette by fourth grade. Therefore, it is urgent to prevent the children from smoking. Parents have the most influence in this aspect. Children should be informed the harm of smoking in their 3 or 4 ye
A. two fifths
B. 63 percent
C. About one in five
D. 63,000