reason

1.for business reasons，for health reasons，for political reasons等表达方式里该用复数形式reasons。for reasons of space，for reasons of her own等表达方式里也用复数形式reasons。

2.注意下面各句里的斜体字：

• I have reason to call him dishonest.
• I have reason for calling him dishonest.
• I have no reason to call him dishonest.
• I have no reason for calling him dishonest.
• I have every reason to call him dishonest.
• I have every reason for calling him dishonest.
• I have good reason to call him dishonest.
• I have good reasons to call him dishonest.
• I have a reason for calling him dishonest.
• I have reasons for calling him dishonest.
• I do not think I have any reason for calling him dishonest.

不可说my reason to call him dishonest或the reason for me to call him dishonest，该说the reason for my calling him dishonest。

3.the reason for his attitude, the reason for her absence, the reason for my refusal等表达方式里通常用for，偶尔用of。

4.The reason (why) I love him is that he has a perfect character等句子里的that在口语里通常被省去。

5.下面第一句里的due to和第二句里的on account of该删去，第三句里的because最好改作that：

The reason (why) I love him is due to his perfect character.

The reason (why) I love him is on account of his perfect character.

The reason (why) I love him is because he has a perfect character.

6.The reason is（或was），...=The reason is（或was）that...。例如：The reason is, nobody has expected him so early.

7.by reason of（因为…）中没有the。主要是公文英语。