The dangerous semicircle of a typhoon in the Southern Hemisphere is that area（）. ["measured from due south clockwise 180°","measured from due south counterclockwise 180°","to the left of the storm's track","ahead of the typhoon measured from the storm's track to 90°on each side"]
什么是通用飞机的飞行操纵系统？
《危险化学品安全管理条理》共（）章（）条。 ["5；71","7；78","7；74","6；75"]
公安"窗口"单位接待时有哪些礼仪要求？
压力机急停按钮的作用是什么？
通用飞机机体结构通常包括哪些方面？
