在那个时代，奴隶主可以随意买卖奴隶。

In that era, a ___slave-owner could buy and sell slaves at will.

那个工厂主被员工称为当代奴隶主，因为他强迫工人每天工作12小时且不给加班费。

The factory boss was called a modern-day ___slave-owner by workers for forcing them to work 12-hour days without overtime pay.