欲鉴别物质的量浓度都为0.1 mol·L－1的KCl、（NH4）2SO4、NH3

可以使肠内酸化，减少氨吸收的药物是（）。

A.乳果糖

B.左旋多巴

C.肾上腺皮质激素

D.溴隐亭

E.新霉素

The number of people who were invited ____ fifty, but a few of them ____ absent for different reasons.[ ]

A. were; was

B. was; was

C. was; were

D. were; were

____________是税务机关依据税法规定，对纳税人的生产、经营活动进行登记管理的一项法定制度，也是纳税人依法履行纳税义务的法定手续。

化纤制针织或钩编起绒女毛衫

家用燃气灶气密性检验，一般采用“U”形管压力计进行，检验以标准工作压力测定，要求（）内无压降。