Why don't you come by [=come over] for a while after dinner?晚餐后过来坐一会儿好吗？

I asked him how he came by the money, but he wouldn't tell me.我问他是如何得到这笔钱的，但他不愿告诉我。

A good job is hard to come by. [=it's hard to get a good job]找个好工作非常不容易。