CRJ900系列飞机有13个外部门（包括选装的后勤务门）。其中有多少个可以用来应急撤离？The CRJ900 series aircraft have 13 external doors (including optional AFT Service Door). How many of them can be used for emergency evacuation?

A. 顶板 Overhead panel

B. 左和右仪表板 Left and right instrument panels

C. 上部操纵台Upper pedestal

D. 下部操纵台 Lower pedestal

A. 水汽含量增加

B. 相对湿度增大

C. 相对湿度减小

A. 最晚在程序转弯之前襟翼20°要设置到位，保持襟翼20°的速度程序转弯。Flap 20°shall be set in position at the latest before the procedure turn, maintain flap 20° speed to make the procedure turn.

B. 如果直线进近，在距离IF 点或等同于IF 点的位置前3-5 海里，襟翼20°要设置到位。If it’s a straight approach, the flap 20°shall be set in place 3 to 5 nautical miles before the IF point or any point equivalent to the IF.

C. 当IF 点或等同于IF 点的位置距接地点小于8 海里时，襟翼20°要在距离接地点12 海里前的位置设置到位。If the IF point or the point equivalent to the IF is located less than 8 nautical miles from the touchdown point, the flap 20°shall be set in position 12 nautical miles away from the touchdown point.

D. 当IF 点或等同于IF 点的位置距接地点小于8 海里时，襟翼20°要在距离接地点10 海里前的位置设置到位。if the IF point or the point equivalent to the IF is located less than 8 nautical miles from the touchdown point, the flap 20°shall be set in position 10 nautical miles away from the touchdown point.

A. 不可以

B. 可以

A. 标准气压10000尺 10000 ft on standard/QNE

B. 修正海压10000尺 10000 ft on QNH

C. 机场标高10000尺 10000 ft on airport elevation

A. 18260FT

B. 19340FT

C. 20660FT

A. 形成西风，风速增大；

B. 风向向顺时针方向偏转，风速增大；

C. 风向向逆时针方向偏转，风速增大

A. 积雨云

B. 浓积云

C. 堡状高积云