Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible.

Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible.

用比空气还重的机器飞行是不切实际的，即使不是完全不可能的，也是微不足道的。

-- Simon Newcomb 西蒙·纽科姆