副詞 for one:

1. as a particular one of several possibilities

1. For one thing they keep the water clean.
   一方面，他們可以保持水的清潔。
2. He was absent from the meeting for one reason or another.
   他為某種理由而沒有出席會議。
3. For one reason or another, she committed suicide.
   不知什么原因，她自殺了。
4. He made a resolution to read something profitable for one hour every day.
   他下決心每天要讀一小時有益讀物。
5. He was exiled from the country for one year.
   他被放逐一年。
6. The thief was put into prison for one year.
   小偷被監(jiān)禁一年。
7. We will lease you the house for one year.
   我們將把這房子租給你一年。
8. For one week the price will be500 dollar.
   住一星期租金是500美元。