1. The river swarmed with piranha, the flesh-eating fish that hunted in packs and could easily strip a cow to its bare bones within a minute.
    河里到处都是食肉鱼，这种食肉鱼成群结队觅食，不到一分钟就能把一头牛吃得只剩下一副骨架。

2. Nothing happened. For some reason the piranha weren´t there.
    什么都没发生。不知是什么原因，那些食肉鱼不在那里。