In those days, many children were put to bed before dark in the summer months.那时夏天的几个月里，很多小孩子都是天黑以前就被打发上床的。It's getting late - I think we should turn back before it gets dark.天色已晚，我想在天黑以前我们应该回去了。We'd better try and finish this job before dark.我们最好努力在天黑以前完成任务。