《海国图志》的作者是____,他提出了“____”的主张。
如图所示,用细线悬挂的矩形AB长为a,其下方固定一长为b的无底圆筒CD,B、C两点间的竖直距离是h.若将细线剪断,矩形AB做自由落体运动,则:
There is _________ in today's newspaper. It's boring.