The door is made of carbon fiber reinforced plastic.

A. The Boeing 747 symbolizes the beginning of a new ear in air transport.

B. The Boeing 747 is the first type of airplane in air transport.

C. Modern air transport started from the Boeing 747.

A. 检查和观察是用于检查飞机内部和周围的舱室和设备的窗口，包括透明材料、框架等。

B. 检查窗和观察窗是用于检查飞机内部和飞机上的舱室和设备的窗口，包括透明材料、框架等。

C. 检查和观察是用于检查飞机内部和周围的舱室和设备的窗口，包括透明材料、其框架等项目。

A. 电源系统讲的是发电、控制和向其他系统提供交流或直流电的组件和部件，包括发电机、继电器、变流器、电瓶等。

B. 电源系统讲的是发电、控制和向其他系统提供交流或直流电的组件和部件，包括发电机、继电器、整流器、电瓶等。

C. 电源系统讲的是发电、控制和向其他系统提供交流或直流电的组件和部件，包括发电机、继电器、静变流器、电瓶等。

A. The localizer beam is aligned with the centerline of the runway.

B. The localizer way is misaligned with the centerline of the runway.

C. The localizer course is aligned with the centerline of the runway.

A. The Unusual Procedures Check List should be in concrete, abbreviated form.

B. The Emergency Procedures Check List should be in constant, abbreviated form.

C. The Abnormal Procedures Check List should be in concise, abbreviated form.

A. If the aircraft is parked on the ground, make sure that wheel chocks are placed.

B. If the aircraft is parked on the ground, make sure that wheel chocks are in position.

C. If the aircraft is parked on a slope, make sure that wheel chocks are in position.

A. Make a little oil to the threads of the two bolts.

B. Apply a small quantity of oil to the threads of the two bolts.

C. Apply a small quantity of oil to the threads of the two nuts.

A. STE规范表达内容的方式，但不规范格式(例如，字体、编号等)。

B. STE管理规范的内容而不是格式 例如（字号，编码等）。

C. STE被用于规范内容的形式而不是版式（ 例如字号，数字等）。

A. Get approval for all modifications from the design authority.

B. The design department is irresponsible for approving the changes.

C. The arrangement has to be approved by the design department.

A. 从安装位置向上提起气瓶。

B. 向上提起做动筒到安装位置。

C. 提起并安装气缸到位。