due用法1
表示“到期的”、“应付(给)的”、“到期应付的”，通常只用作表语。如：
The bill is due. 这张票据已到期。
My salary is due tomorrow. 我明天领薪。
表示应付给或应给予某人，通常与介词 to 连用。如：
A great deal of money is due to you. 要付给你一大笔钱。
Respect is due to older people. 年长者应受到尊重。
Our grateful thanks are due to you. 我们衷心感谢你。
due用法2
表示“预定的”、“约定的”、“预定要到达或发生的”，也通常用作表语。如：
When is the train due? 火车什么时候到?
I’m due for a pay rise soon. 我不久就要加薪了。
其后可接不定式。
The guests are due to arrive very soon. 客人很快就会到。
The meeting isn’t due to start until four. 会议预定要到四点才召开。
due用法3
表示“适当的”、“合适的”、“应得的”，通常只放在名词前作定语。如：
We should pay due attention to this problem. 我们应对这个问题给予适当的注意。
You must put these things in due order. 你必须把这些东西按适当的顺序放好。
due用法4
用于 due to(由于，因为)。按照传统语法 due to 主要引导表语，一般不引导状语。如：
His absence was due to the storm. 他因暴风雨而缺席。
Her success was due to her hard work. 她成功是因为她努力工作。
但是在现代英语中，due to 也可用来引导状语。
He was late due to the very heavy traffic. 由于交通拥挤他迟到了。