knock against each other的用法和樣例：
例句
- Where there are two, it's the second that clangs against the first and makes noise.
戴雙鐲的手臂，鐲子互撞發(fā)出叮當響聲。 - But during the collision, one galaxy can rip the other apart gravitationally, and dust and gas common to both galaxies does collide.
當星系互撞期間，星系可能因重力拉扯另外一個(gè)星系，塵埃與云氣也會(huì )因此而合并。
