2--Everybody knows Americans burn a lot of oil, but is there a special oil that they burn in the middle of the night?
 
1--I have big exam tomorrow.
 
2--Are you prepared?
 
1--No, not at all! I have to burn the midnight oil, I need to do well on this exam.
 
2--Americans are not burning a special oil reserved for the middle of the night, they are just staying up very late.
 
1--This actually makes sense if you think of a candle, or a lantern, and you have a lot of work to do, that may take you all night.
 
2--This is a phrase everybody will understand, and you can use this phrase when you have a lot of work to do, and not that much time to do it in.
 
===================================
注解：
 
1.confusing令人困惑  
2.special专门的   
3.reserved矜持的

===================================
译文：
 
1--有时候，美语有些糊里糊涂的，很费解，就比如：burn the midnight oil（挑灯夜战）。
2--大家都知道美国人要烧掉很多油，但是这里是有一种专门在晚上烧的油么？
1--我明天有场重要的考试。
2--你准备了么？
1--没有，没怎么准备。我今天不得不挑灯夜战（burn the midnight oil），我需要取得一个不错的成绩。
2--美国人不是晚上才去烧什么特别的油，他们只是要熬夜到很晚。
1--如果你想想蜡烛、提灯，就能够明白短语的意思了。有很多工作要做，这也许会花费整晚的时间。
2--这是一个众人皆知的短语。当你有很多事情要做或者没有太多时间做某事的时候，你就可以使用这个短语。