When _____ he come here? [ ]
A. is
B. was
C. does
D. did
答案：D
电阻并联时，电阻值大的电阻通过电流小。（）
用于剧烈干咳伴胸痛
A．喷托维林(咳必清，维静宁)B．可待因C．氯哌斯丁(咳平)D．乙酰半胱氨酸E．溴己新
