Most secondary structures are important to the performance of the airplane.

A. For release with the ground preconditioned air connection single valve inoperative in the open position, do these steps.

B. For dispatch with the ground preconditioned air connection check valve inoperative in the open position, do these steps.

C. For release with the ground reconditioned air connection check valve inoperative in the open position, do these steps.

A. Be sure that the hose is not blocked.

B. Make sure that the tubes have no deformation.

C. Ensure that the pipes are not damaged.

A. 为防止外来物摩擦，对表面抛光。

B. 为防止不必要的磨损，对表面进行打磨修理。

C. 对表面进行抛光以防止不必要的磨损。

A. The valve has flaps shaped like a full circle.

B. The shape of the valve flaps is a half ring.

C. The valve flaps have a shape of half circle.

A. 拧紧这些同轴接头（用手上紧再1/8转）

B. 拧紧这些同轴接头（用手上紧少1/8转）

C. 拧紧这些同线路接头（用手上紧少1/8转）

A. 描述飞机起落架时，应说明应急展开系统。

B. 描述飞机起落架时，应描述起落架应急放出系统。

C. 描述飞机起落架时，应说明应急逃生系统。

A. 确保能用耳机听到飞行语音记录。

B. 确保能通过耳机与客舱进行对话。

C. 确保能在耳机里听到驾驶舱的对话。

A. This program is partially important to type B parts.

B. This procedure is of particular importance to type B parts.

C. This procedure is not especially important to type B parts.

A. 装配之前，确保适当减少减震器里的压力。

B. 拆卸之前，确保释放减震器里的初始压力。

C. 分解之前，确保减震器里的所有氮气压力已释放。

A. Make sure that the service control unit is in the open position.

B. Make sure that the servo control unit is in the right position.

C. Make sure that the servo control unit is in the open position.