下列平喘药物中，属于β-受体激动剂的是（）
A.茶碱
B.麻黄碱
C.酮替芬
D.色甘酸钠
E.异丙托溴铵
参考答案：B
教师是履行（）职责的专业人员
A.教育教学
B.教书育人
C.教学管理
The Olympic Games were watched by ______ billions of people around the world.
A. virtually B. literally C. deliberately D. appropriately
