The hot battery bus usually receives power from the main battery or main battery charger.

A. 给出了允许使用的动词，不要使用未列出的动词形式。

B. 动词以批准的表格列出,不要使用表中未列出的动词。

C. 给出了动词允许使用的形式。不要使用未列出的动词形式。

A. A version means modifying the information in the existing manual.

B. A revise explains correcting information in an old manual.

C. A revision means a modification of information in an existing manual.

A. 本章中任何或所有部件的翻修必须使用部件制造商提供的数据完成。

B. 任何或所有部件的销售必须提供本章有关的部件生产商数据。

C. 本章中任何或所有部件的翻新必须由部件生产商完成并提供数据。

A. 机身站位360处的地板梁有低度腐蚀（长2英寸，直径1英寸）。

B. 机身站位360处的地板梁有重度腐蚀（长2英寸，半径1英寸）。

C. 机身站位360处的地板梁有中度腐蚀（长2英寸，直径1英寸）。

A. 附录应显示系统数据所在的章或子章。

B. 目录应显示章或子章以及系统路径所在的位置。

C. 索引应显示系统电路所在的章或子章。

A. APU start attempts are inhibited above 25,000 feet with both busses off, only one start attempt is allowed below 25000 feet.

B. With both busses power off, APU start attempts is recommended above 25000 feet and only one start could be accepted below 25,000 feet.

C. APU start attempts are not recommended above 25,000 feet. With both busses off, only one start attempt is recommended below 25,000 feet.

A. 描述飞机螺旋桨时，如果合适，应阐述正桨、反桨和反转。

B. 描述飞机螺旋桨时，如适用，应描述顺桨、解除顺桨和反桨相关信息。

C. 描述飞机螺旋桨时，如果合适，应讨论顺桨、不反桨和反推。

A. The user of this schematic diagram is the mechanic.

B. The user of this schematic diagram is the pilot.

C. The user of this schematic diagram is the flight attendant.

A. Another important function of lubricating oil is to protect the corroded metal surfaces.

B. Another important task of the oil is to protect the metal surfaces from corrosion.

C. Preventing the metal surface from further corrosion is the other essential function of the lube.

A. Turn the drain valve counterclockwise to cause the fluid to stop flowing before the valve is pushed.

B. When you turn the drain valve counterclockwise, no fluid will flow until you push the valve in.

C. Make sure there is no fluid flowing after the valve is pushed, then turn the drain valve clockwise.