在运输有轮式部件或重心较高机件时，必须有与平板车为整体的专用架子，且必须（）。
A.固定
B.四人以上作业
C.电机车拖运
参考答案：A
These natural disasters have warned us that everyone should start to protect the _____ immediately. [ ]
A. amusement
B. development
C. environment
D. government
项号栏目应填_____。
A．01
B．02
C．05
D．01,05
