氮气是一中无色、无味、无嗅的惰性气体。
参考答案:对
I went home and _____ my schoolbag and started to help Mother do the cooking. [ ]
A. put off
B. dropped off
C. turned off
D. shut off
医院临床科室是实现医院功能的最基本单位。患者病情的复杂多变,使得临床科室的业务工作具有连续性、应急性和时效性特点。()