简述影响管理幅度的因素。
参考答案：
单孔加工时应遵循先中心占领头后钻头钻孔，接着镗孔或铰孔的路线。
On a ship，a door that is required to be marked KEEP CLOSED is designed to（）.
A.prevent the passage of flammable gases
B.prevent the passage of poisonous vapors
C.delay the spread of heat and flames
D.maintain watertight integrity
