麻醉药品和精神药品专用处方的格式由（）规定
A、市级卫生主管部门
B、国务院卫生主管部门
C、省级卫生主管部门
D、医院领导
参考答案：B
—How long has the nationwide ban (禁止) on plastic bags been put into practice?
— _______ the beginning of June. [ ]
A. Behind
B. Since
C. Among
D. At
矿物质的主要营养作用有哪些？
