下列哪个房间可不设机械排风?()
A.公共卫生间
B.高层住宅暗卫生间
C.旅馆客房卫生间
D.多层住宅有外窗的小卫生间
参考答案:D
Just as a famous Chinese saying goes, a timely heavy snow is a ______ of good harvest next year.
A.mark
B.track
C.sign
D.appearance
微粒扩散的微观基础是()。