青霉素的抗菌谱是()
A.绿脓杆菌
B.草绿色链球菌
C.肺炎球菌
D.破伤风杆菌
E.变形杆菌
参考答案:B, C, D
All passengers _____ are expected to fasten the seat belts when the plane takes off and lands. [ ]
A. on aboard
B. on board
C. on the board
D. on boards
简述艺术批评的功能。