962、If you do not install the rigging pin, the elevators, will move down when there is no pressure in the system

　The rigging pin can prevent the elevators from retracting and expanding when the system is de-energized.

　After the system is pressurized, the elevators will drop down no matter where the rigging pin is installed.

　Without the rigging pin, the elevators will go down when there is no pressure in the system.

正确答案：C

解析：

解析:注释: move down=go down 向下移动。

526、This can cause a deterioration of the mechanical properties of the assembly.

525、Inspection of the lavatory rapid-decompression device.

524、Assemble the unit

523、用清洗液对腐蚀进行清洁时,要避免损坏周围区域。

522、确保传感器处无液压油渗漏

521、The exit doors used, to facilitate evacuation that are not normally used for exit. 使用的出口门，以方便疏散，通常不用于出口。

520、有必要对这些区域进行频繁检查。

519、 when there is no technical name in approved nomenclature, select one that is short and easy tounderstand.

518、警告信息是一项操作步骤、检查、修理或维护操作，如果不正确执行可能导致人员受伤或死亡。

517、当通风空气温度升至 27℃时，排气阀打开。