Machines such as trebuchets were the heavy artillery of the pre-gunpowder era.

而抛石机这类机，火药时代的重型火炮。

But along this stabilized shoreline here where we have riprap or large boulders, we have corals that have settled and are thriving.

但这条定的海岸线上有抛石或巨大的巨石，有珊瑚定这里茁壮成长。

A trebuchet consists of a long beam attached to a pivot rod on a heavy frame.

抛石机由一个带转轴的长梁连接底座上构成的。

Behind me is a replica of a small siege  engine called a perrier.

我身后一个叫做抛石机的小型围攻械的复制品。