“在古代”的英语可以翻译为：in ancient times ...

在古代，狗也与治病有关。Dogs were also associated with healing in the ancient world.铅是早在古代就已知的金属之一。Lead was one of the metals known to the ancient world.有一些湿地在古代就形成了。There are some areas of wetland which are of ancient origin....