Specific duties are levied （） some physical unit such as dollars per bushel, per kilo, or per metre and ad valorem duties are calculated as a percent of the value of the goods.

A. on the basis of

B. with the basis of

C. on the base of

D. with the base of

服药后出现头痛的不良反应时可服用

A．维生素B₆
B．阿司匹林
C．阿托品
D．牛奶
E．咖啡