在标签上，看一下上次检查的日期。

A. Move it lightly and make it through the hole

B. Move it slightly to make it aim at the hole

C. Move it gently to make it enter the hole

A. The aircraft safety should be ensured.

B. The flight safety must be assured.

C. The navigation safety must be insured.

A. 确保行李箱已空。

B. 确保厨房柜已空。

C. 确保卫生间已空。

A. The engine sump and gearboxes are connected internally.

B. There are also internal connections between the engine sumps and gearboxes.

C. Internal arrangement of wires exist between the engine sump and gearboxes.

A. Crucial angle of attack is the angle at which a stream or air flow begins to split from a surface,causing a decrease in efficiency. It is important for designing dynamic surfaces ,such as airplane wings,turbine blades,as it determines the maximum attack angle that can be achieved without causing loss of lift or thrust.

B. Crutial angle of attack is the angle at which a stream or air flow begins to seperate from a surface,causing a decrease in efficiency. It is important for designing aerodynamic surfaces ,such as airplane airfoils,turbine blades,as it determines the maximum attack angle that can be achieved without causing loss of lift or thrust.

C. Critical angle of attack is the angle at which a fluid or air flow begins to separate from a surface, causing a reduction in the efficiency of the flow. The critical attack angle is an important consideration in the design of aerodynamic surfaces, such as airplane wings, turbine blades, as it determines the maximum angle of attack that can be achieved without causing a loss of lift or propulsion.

A. The computer needs to be backup at each interval.

B. The backup of the computer is necessary.

C. Back up your computer regularly.

A. It is suggested that nickel plated corrosion resistant steel or nickel plated steel fittings be used as alternatives for aluminum fittings in the high pressure and normal brake return systems between the antiskid module and parking brake module.

B. Suggest to use vanadium plated corrosion resistant steel or vanadium plated steel fittings as alternatives for aluminum fittings in the high pressure and normal brake return systems between the antiskid module and parking brake module.

C. It is recommended that cadmium plated corrosion resistant steel or cadmium plated steel fittings be used as replacements for aluminum fittings in the high pressure and normal brake return systems between the antiskid module and parking brake module.

A. 前段包括以下信息。

B. 封面部分包括以下信息。

C. 前言部分包括以下信息。

A. 如果可能的话，告诉你的读者如果不遵守安全指令会发生什么。

B. 如果必要的话，告诉你的读者如果没有安全指令会发生什么。

C. 如果可能的话，告诉你的读者会发生什么，判断是否未遵守安全指令。

A. 在铝合金部件上不要使用藏红花布，它含有氧化铁，在铝合金部件上会造成划痕。

B. 在铝质部件上不要使用细砂布，细砂布含有氧化铁，在铝质部件上会造成腐蚀。

C. 在铝合金部件上不要使用细砂布，细砂布含有氧化铁，在铝合金部件上会造成腐蚀。