darken是一个英语动词，基本意思是“使变暗，变黑”，引申还可指“忧郁，生气，不快”。第三人称单数：darkens；现在分词：darkening；过去式：darkened；过去分词：darkened。
例句：
1、It was a tragedy that darkened his later life.
这场悲剧给他后来的岁月蒙上了阴影。
2、The sky began to darken as the storm approached.
暴风雨来临时天空变得黑沉沉的。
3、As the day darkened the streetlights came on.
天色渐暗，街灯亮了。