下列人物哪位不是以国家为中心的政治经济学的代表人物：

单项选择题使用电光分析天平时,取放物体时要托起横梁是为了（）。

单项选择题The most effective way to deal with an episode of disorientation in flight is to（ ） A. keep a constant look-out for glimpses of the natural horizon outside B. rely absolutely on the aircraft instrument C. keep the control column central and maintain a constant power