打瞌睡英语叫做 "to doze off" 或 "to nod off." 这个说法源自于人们在睡觉时会不时地打个盹儿，眼皮轻轻地闭上，头也会微微垂下。

例句：

I couldn't help but doze off during the boring lecture. (我在沉闷的演讲中忍不住打了个盹儿。)

She nodded off on the train ride home. (她在回家的火车上打了个盹儿。)