用钢笔描红。
高兴 煤炭 富饶
Gangnam Style was issued in the middle of July last year, then it ____.
如图所示,两端开口的弯管,左管插入水银槽中,管内外高度差为h1,右管有一段水银柱,高度差为h2,中间封有一段空气.则不正确的是( )