1 certain /ˈsɚtn̩/ adjective Learner's definition of CERTAIN
1
not used before a noun,
[more certain; most certain] : not having any doubt about something : convinced or sure确信；无疑；肯定 -
Are you certain [=sure] you want to leave today?你真的想今天走？
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I feel less than certain about it. [=I am not sure about it]这件事我不太确定。
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She's certain (that) she can do the job despite her lack of experience.尽管她缺乏经验，但她确信能胜任这个工作。
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I'm fairly certain that I'll be on time.我肯定会准时的。
2
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used with it to say that something is known to be true or correct可靠的，确定的（与it连用） -
Although little is known about these ancient people, it is certain that they grew a number of crops.尽管人们对这些古代人知之甚少，但他们肯定种过许多种作物。
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It's not certain [=definite] that the company will lay off workers. [=the company may lay off workers, but it also may not]公司是否会裁员尚不清楚。
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It seems certain that the jury will convict him.看样子陪审团一定会判他有罪。
3
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used to say that something will definitely happen or that someone will definitely do something有把握的；必然的；肯定的 -
Before the game was half over our team's defeat was nearly certain.比赛还没进行到一半，我们队的败局就几乎已定。
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Contact with the poison means certain death.接触这种毒药必死无疑。
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Her victory seems certain.她似乎稳操胜券。
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often followed by to + verb常接动词不定式 -
As technology develops, the rates of success with the procedure are certain to improve.随着技术的进步，这道工序的成功率肯定会提高。
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Health-care costs are certain [=sure] to increase in coming years.未来几年，医疗成本肯定会增加。
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She is almost certain to win.她几乎已胜券在握。
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He's all but certain to say no. [=he will almost surely say no]几乎可以肯定他会拒绝。
4
always used before a noun —
used to refer to something or someone that is not named specifically某个，某些，某种（用于指未特别指明的人或事） -
Each employee will receive a certain share of the profits.每位员工都将得到一定份额的利润分成。
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Building even a simple bookcase takes a certain amount of skill. [=takes some skill]即便做一个简单的书柜也需要一定技巧。
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Certain people are always late for dinner.某些人总会在晚饭时迟到。
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On certain days there is no parking on the street.在某些特定日子，街上是不准停车的。
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The new technology has certain limitations.这项新技术存在一些缺陷。
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Students must fulfill certain requirements to graduate.学生们必须达到某些要求才能毕业。
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She's allergic to certain [=particular] foods.她对某些食物过敏。
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The contract can be extended under certain circumstances. [=in some special cases]合同在特定情况下可以延期。
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To a certain extent [=up to a point] he's right.在一定程度上，他是对的。
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The movie will appeal to people of a certain age. [=people who are no longer young]中年人会对这部电影感兴趣。
a certain
1
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used to refer to a quality that is noticed but that is difficult to explain or describe某种（显而易见却难以描述的品质） 2
formal —
used with the name of a person you do not know某某，某位，一个叫…的人（与陌生人的姓名连用）
for certain
: without a doubt : definitely or certainly肯定；确定；无疑
make certain
: to do something or find out something so that you have no doubt about whether something is true, correct, will happen, etc.对…确认；弄清楚；弄明白 -
Make certain (that) you lock the door when you leave. = Make certain to lock the door when you leave.你离开时一定要把门锁好。
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We must make certain [=make sure] this doesn't happen again.我们必须确保这样的事情不再发生。
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She made certain she thanked each of them for coming.她确保自己向每位来宾都表达了谢意。
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sometimes + of 2 certain /ˈsɚtn̩/ pronoun
2 certain
/ˈsɚtn̩/
pronoun
Learner's definition of CERTAIN
formal
: certain ones : particular members of a group : some某些；某些人 —
+ of