治疗癌症晚期顽固性疼痛的药物是()。
A.强麻醉性镇痛药(吗啡、哌替啶)
B.非类固醇抗炎药
C.弱阿片类(可待因、芬太尼)
D.三环类抗抑郁药
E.苯二氮类
参考答案:A
While there are quite a few differences in the education system, in many countries education is ____.
A.usual
B.regular
C.normal
D.universal
氟气是氧化性最强的非金属单质,在加热条件下,等物质的量的氟气与烧碱完全反应,生成NaF、H2O和另一种气体,该气体可能是( )。
A.H2
B. HF
C.O2
D.OF2