due用法1
表示“到期的”、“應付(給)的”、“到期應付的”，通常只用作表語。如：
The bill is due. 這張票據已到期。
My salary is due tomorrow. 我明天領薪。
表示應付給或應給予某人，通常與介詞 to 連用。如：
A great deal of money is due to you. 要付給你一大筆錢。
Respect is due to older people. 年長者應受到尊重。
Our grateful thanks are due to you. 我們衷心感謝你。
due用法2
表示“預定的”、“約定的”、“預定要到達或發生的”，也通常用作表語。如：
When is the train due? 火車什么時候到?
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. 客人很快就會到。
The meeting isn’t due to start until four. 會議預定要到四點才召開。
due用法3
表示“適當的”、“合適的”、“應得的”，通常只放在名詞前作定語。如：
We should pay due attention to this problem. 我們應對這個問題給予適當的注意。
You must put these things in due order. 你必須把這些東西按適當的順序放好。
due用法4
用于 due to(由于，因為)。按照傳統語法 due to 主要引導表語，一般不引導狀語。如：
His absence was due to the storm. 他因暴風雨而缺席。
Her success was due to her hard work. 她成功是因為她努力工作。
但是在現代英語中，due to 也可用來引導狀語。
He was late due to the very heavy traffic. 由于交通擁擠他遲到了。