over在本句中相当于while having/doing，意为“一边...一边; 在(做)...的时候”。如： fall asleep over one's work 工作时睡着了 talk over a cup of tea 一面喝茶, 一面谈话 during 意为“在...期间”，强调在一段时间之内。如： They swim every day during the holidays. 他们在假期天天。 The sun gives us light during the day. 太阳在白天给我们阳光。 He fell asleep during the lesson. 他在上课时睡着了。 for常接一段持续的时间或距离。请看例句： We ran for two miles. 我们跑了两英里。 He stayed for a week. 他待了一周。 We haven't seen each other for ages. 我们好久没见面了。 I have been waiting for you for two hours! Whare have you been? 我一直等了你两个小时！你去哪儿了？ 学英语的时候，要多看一些例句，这样才能更好地理解不同词汇在句子中的区别和用法。 祝你进步！