英汉词典

1. 肯定的;有把握的;毫无疑问的
    If you are certain about something, you firmly believe it is true and have no doubt about it. If you are not certain about something, you do not have definite knowledge about it.

    e.g. She's absolutely certain she's going to make it in the world...
           她坚信自己会出人头地。
    e.g. We are not certain whether the appendix had already burst or not...
           我们不敢肯定阑尾是否已经破裂。

2. 必然的;必定的;肯定的
    If you say that something is certain to happen, you mean that it will definitely happen.

    e.g. However, the scheme is certain to meet opposition from fishermen's leaders...
           然而，这项计划一定会遭到渔民领袖的反对。
    e.g. It's not certain they'll accept the Front's candidate if he wins...
           即便来自阵线的候选人获胜，他们能否接受他还说不准。

3. 确凿的；无疑的
    If you say that something is certain, you firmly believe that it is true, or have definite knowledge about it.

    e.g. One thing is certain, both have the utmost respect for each other...
           有一点可以肯定，那就是双方都非常尊重对方。
    e.g. It is certain that Rodney arrived the previous day.
           罗德尼肯定是头天到的。

4. 确实的;肯定的
    If you have certain knowledge, you know that a particular thing is true.

    e.g. He had been there four times to my certain knowledge.
           我确定他去过那儿4次。

5. 确切地;无疑地
    If you know something for certain, you have no doubt at all about it.

certain的反义词

    e.g. She couldn't know what time he'd go, or even for certain that he'd go at all...
           她不知道他何时走，就连他到底走不走都说不准。
    e.g. Hill had to find out for certain.
           希尔得弄个清楚。

6. 确保；保证
    If you make certain that something is the way you want or expect it to be, you take action to ensure that it is.

    e.g. Firstly, they must make certain that their pension needs are adequately catered for...
           首先，他们得确保他们能获得足够的养老金。
    e.g. To make extra certain, a police helicopter kept watch from the skies.
           为确保万无一失，一架警用直升机一直在空中警戒。