公众聚集场所在营业期间的防火巡查应当至少（）一次。
A、每日
B、每半小时
C、每一小时
D、每二小时
参考答案：D
These toys are not suitable for children _____ four years old, who are too young. [ ]
A. outside
B. beyond
C. under
D. within
筋将衰惫之象为
A．面色萎黄B．面黄虚浮C．面黄鲜明如橘皮色D．面黄晦暗如烟熏色E．红黄隐隐，明润含蓄
