当EEC自动点火功能失效后哪些情况下必须打开空中点火开关?
A. 起飞着陆
B. 结冰、大雨或者大雾天气
C. 空中颠簸飞行
D. 以上都是
Which of the following is associated with consistently high barometric pressure ().
A. The horse latitudes
B. The doldrums
C. The prevailing westerlies
D. The trade winds
根据GB3787-83的规定,Ⅲ类手持电动工具的绝缘电阻不应低于1MΩ。()