certain
1. be certain of : 确信, 对...有把握；
2. for certain : 肯定地；
形容词
1. He is certain to come.
他一定会来的。
2. The evidence is certain and the facts are clear.
证据确凿，事实清楚。
3. I was certain that he had seen me.
我肯定他已看见了我。
4. A certain person called on you yesterday.
昨天有个人来拜访过你。
5. It is certain that two and two makes four.
二加二等于四是确定无疑的。
1. 肯定：股票市场最难搵到投资对象日子,就系大家对前景好肯定(certain)之时;反之,机会处处往往系股市进入不稳定期(uncertain times). 今年1月人人话内地A股出现泡沫,就系另一投资内地股票时机,反而依家人人改变睇法,认同唔系泡沫,便要小心D.
2. 确定：中国证监会前副主席史美伦就曾经指出,上市公司质量问题、高管人员圈钱、大股东占用公司资金等等行为是很严重的问题,证监会现在很重视这个问题. 对于这些行为的执法也非常重要,因为监管的含义就是制定法律和执行法律,为市场提供比较清楚(clear)确定(certain)的法律,而不能朝令夕改.
肯定（BEING SURE）
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。
肯定（BEING SURE）
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。
了解海关手续
A：You've traveled abroad a lot, Jim, so would you like to tell me something about clearing customs.
吉姆，你经常出国旅游，能向我介绍一下关于通关的情况吗？
B：When you arrive in a country, you clear customs. A lot of countries have two channels: the green channel and the red channel. Some countries, like India, have three channels: the white channel, the green channel and the red channel.
到达一个国家时要通关。许多国家的海关有两种通道：绿色通道和红色通道。还有些国家如印度有三种通道：白色通道、绿色通道和红色通道。
A：Then what are the differences between the green channel and red channel?
那么绿色通道和红色通道之间有什么区别呢？
B：If you have more than the duty-free allowances or prohibited goods, you go through the red channel and declare them to a customs officer. If you otherwise have nothing to declare, you go straight through the green channel unless you are asked to stop by an officer. 如果你携带的东西超出免税的范围或属于禁带物品，你
就得从红色通道通过并向海关官员申报物品。如果你没有需要申报的物品而海关官员又没有阻拦你，你就可以直接通过绿色通道了。
A：I see.I'm told that we'll have to state the purpose of going to a certain country, is it true?
我明白了。我听说去一个国家时需要陈述旅行的目的，是吗？
B：That's right. People go aboard for different purposes: some for pleasure, some on vacation, some on business, and some for other purposes.
是的。人们出国都各有目的：有的为了消遣，有的出去度假，有的是因公出差，有的是为了其他目的。
A：I'm going to New Zealand for sightseeing. What should I say if they ask about my purpose?
我要去新西兰观光，如果他们问我旅行的目的我该怎么说呢？
B：Just saying "sightseeing" is OK.
说"观光"就行了。