形容词 “certain” 可以表示 “确定的，肯定的”。常用搭配有 “for certain” 和 “be certain about something”。此外，“certain” 还可以用来在不提供细节的前提下表示 “某个特定的人或事物”。这个视频教你 “certain” 的常见用法。

1. 形容词 “certain” 可以表示 “百分百确定的，有把握的”。

I am certain that Tuesday is the day before Wednesday.

Are you certain we are at the right place?

2. 搭配 “for certain” 表示 “肯定地，确定无疑地”。

Tuesday comes before Wednesday, for certain.

He can't say for certain whether they'll be on time or not.

3. 搭配 “be certain about something” 表示 “对某事有把握、很确定”。

I am certain about the length of this video. It's one minute long.

She is certain about the date of the event.

4. “Certain” 还可以表示 “某个，某些，某位”，代指 “事物或人”，但不提供具体细节。

Hello? Boss? For certain personal reasons I can't come to work today.

Certain foods are easier to buy than others.