题目内容：
根据材料回答题,Smoking, which may be a pleasure for some people, is a serious source of discomfort for their fellows. _51_, medical authorities express their concern about the effect of smoking _52_ the health not only of those who smoke but also of those who do not. In fact, non-smokers who must involuntarily inhale (吸入) the air _53_ by tobacco smoke may suffer more than the smokers _54_. Smoking is prohibited in the theatres and in halls used for showing films _55_ in laboratories _56_ there may be a fire hazard (危险). Elsewhere, it is up to your good _57_.
I am _58_ asking you to maintain “No-Smoking” in classrooms and seminar rooms.
This will prove that you have the _59_ health in mind, which is very important to a large _60_ of our students.
A．Still
B．Further
C．More
D．Again
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