简述系统研究方法的特点？

测得血糖20天室内质量控制数据，计算出其均值为5.0mmol/L，标准差为0.25mmol/L，其变异系数应为()

A．1%

B．2%

C．3%

D．4%

E．5%

He has supper at home everyday. He ___________ eats out. [ ]

A. sometimes

B. never

C. often

—Would you like to come to my house for dinner tonight?

—I'd love to, _____ I have lots of work to do. [ ]

A. so

B. or

C. and

D. but

与弱脉具有共同脉象特征的是（）。

A.沉细虚

B.微细

C.濡细

D.细虚濡

E.沉缓

主要用于吗啡和哌替啶急性中毒解救的药物是

A．纳洛芬
B．阿托品
C．氯丙嗪
D．吲哚美辛
E．纳洛酮