certain

确信的、有把握的

I'm not certain whether the store opens on Sundays.

我不确定那家店星期日有没有开。

某个、某一、某些用于名词前

Certain students were asked to stay after class.

某些学生被要求下课后留下来。

一定的、某种程度的

The job requires a certain amount of patience.

这份工作需要一定程度的耐心。

必然的、难免的

Without more funding, the project's failure is certain.

若没有更多资金，这个专案必然失败。

确实的、无疑的较正式

One thing is certain: prices will rise again next year.

有一件事是确定的：明年物价还会再涨。

确实、肯定for certain

Nobody knows for certain what caused the power outage.

没有人确实知道这次停电的原因。

确认、弄清楚make certain

Please make certain that all the windows are locked.

请确认所有窗户都已锁好。