碱度测定的结果是酚酞碱度等于甲基橙碱度,该水样中反映碱度的离子有()。
A、OH和HCO
B、CO无OH和HCO
C、OH无CO和HCO
D、OH无CO
参考答案:C
Mary as well as her sisters _____ Chinese in China. [ ]
A. are studying
B. have studied
C. is studying
D. study
关于硝酸甘油的叙述错误的是
A.扩张静脉血管,降低心脏前负荷
B.扩张动脉血管,降低心脏后负荷
C.减慢心率,减弱心肌收缩力而减少心脏作功
D.加快心率,增加心肌收缩力
E.减少心室容积,降低心室壁张力