If one or more blades are missing, make an entry in the engine logbook.

A. 用干净的毛巾清洁表面。

B. 用干净的布擦表面。

C. 用干布擦表面。

A. It is possible to mix appropriate engine oils agreed by engineers .But we suggest that you use the identical oil agreed by the same manufacturer.

B. It is possible to mix approved engine oils. But we recommend that you use the same approved oil from the same manufacturer.

C. It is possible to mix engine oils authorized by the same manufacturer. But we suggest you use the same oils authorized by the engineers.

A. 设备清单应包含特定飞机在交付时已安装的所有必需或选装设备。

B. 交付时，应按照设备清单在具体飞机上安装所有必要或选装设备。

C. 设备清单应包含送达时在具体飞机上安装的所有要求或选装设备。

A. 此步骤可以确保燃油泵工作正常。

B. 燃油泵必须要经过这个阶段才能正常工作。

C. 通过这个步骤保证燃料能够到泵的位置。

A. Clean all lint, dust and debris from the ventilation holes located on the aft side of the captain＇s primary flight, navigation, and center lower engine display units.

B. Clean the vent holes behind the captain＇s primary flight, navigation and lower middle engine display units which are blocked by lint, dust and debris.

C. The captain＇s primary flight, navigation, and center lower engine display units must be cleaned since the ventilation holes behind them are clogged by lint, dust and debris.

A. If you drink contaminated water , illness must happen.

B. You may be in trouble, if you drink bacteria free water.

C. If you drink water that contains bacteria, you will get sick.

A. Procedures shall be omitted for coping with cases of smoke and/or fire in the cabin or from an engine in the following flight segments.

B. Procedures shall be provided for accompany with cases of smoke and/or fire in the cabin or from an engine in the following flight sectors.

C. Procedures shall be provided for coping with cases of smoke and/or fire in the cabin or from an engine in the following flight phases.

A. 为了供应充足，沿着侧壁和天花板中心的出口将空气分离。

B. 为了供应不过量，沿着侧壁和天花板中心的出口将空气分离。

C. 为了供应对称均衡，沿着侧壁和天花板中心的出口将空气分离。

A. 小心地展开薄板。

B. 小心地合上铝片。

C. 小心地打开钢片。

A. In procedural sentences, you can use a maximum of 20 words before the comma.

B. In procedural sentences, you can use a maximum of 20 words before the colon.

C. In procedural sentences, you can use at least 20 words before the full stop.