sure, certain, definite, positive

形容詞 certain:

1. definite but not specified or identified
2. having or feeling no doubt or uncertainty; confident and assured
   同義詞：sure
3. established beyond doubt or question; definitely known
4. certain to occur; destined or inevitable
   同義詞：sure
5. established irrevocably
   同義詞：sealed
6. reliable in operation or effect
   同義詞：sure
7. exercising or taking care great enough to bring assurance
   同義詞：sure

1. For certain reasons I will be unable to attend the meeting.
   因為某種原因，我不能出席這次會議。
2. I can't say for certain when he will arrive.
   我說不準他什么時候會來。
3. It's certain that every effect must have a cause.
   無疑，每個結果必定有其原因。

cer.tain

adj.（形容詞）
Definite; fixed:
確定的；固定的：
例句：
set aside a certain sum each week.
每周存入一定數(shù)額的存款

Sure to come or happen; inevitable:
一定會來的，必定發(fā)生的；不可避免的：
例句：
certain success.
必然的成功

Established beyond doubt or question; indisputable:
無疑的：確定而不容懷疑或疑問的；不容爭辯的：
例句：
What is certain is that every effect must have a cause.
每一個結果都有一個原因，這是確定無疑的

Capable of being relied on; dependable:
能被依賴的；靠得住的：
例句：
a quick and certain remedy.
快捷而可靠的治療方法

Having or showing confidence; assured.
有信心的，顯示信心的；確定的

Not specified or identified but assumed to be known:
可想而知的：沒有確定或辨別的但假定已知道的：
例句：
a certain popular teacher; felt that certain breeds did not make good pets.
的確是個受歡迎的老師；感覺上有些飼養(yǎng)的方式并沒有培育出優(yōu)良的寵物來

Named but not known or previously mentioned:
某位的：有姓名但不被知道或前面未提到的：
例句：
a certain Ms. Johnson.
一位約翰遜女士

Perceptible; noticeable:
可覺察的；引人注目的：
例句：
a certain cozy charm; kept a certain air of mystery about him.
一種可感知的令人舒服的魅力；他保持一種引人注目的神秘氣息

Not great; calculable:
不大的；可計算的：
例句：
to a certain degree; a certain delay in the schedule.
在一定程度上；安排上的一定的延誤

pron.（代詞）
An indefinite but limited number; some:
某些，一些：一個不確定但有限的數(shù)目；有些：
例句：
Certain of the products are faulty.
有些產品是不合格的

<習慣用語>for certain
Without doubt; definitely.
毫無疑問地；肯定地
來源：
Middle English
中古英語
from Old French
源自 古法語
from Vulgar Latin *cert3nus
源自 俗拉丁語 *cert3nus
from Latin certus [past participle of] cernere [to determine] * see krei-
源自 拉丁語 certus [] cernere的過去分詞 [決定] *參見 krei-

<參考詞匯><同義詞>certain,inescapable,inevitable,sure,unavoidableThe central meaning shared by these adjectives is .impossible to avoid or evade.:
這些形容詞共有的一個中心意思為.不可能避免或躲避.：
例句：
certain death;
必定的死亡；

例句：
an inescapable conclusion;
不可逃避的結局；

例句：
an inevitable result;
必然的結果；

例句：
sudden but sure regret;
突然的但肯定的后悔；

例句：
an unavoidable accident. See also Synonyms at sure
不能避免的事故 參見同義詞 sure

Althoughcertain appears to be an absolute term, it is frequently qualified by adverbs,as infairly certain or quite certain. In an earlier survey,a majority of the Usage Panel accepted the construction
盡管certain 像一個獨立的詞， 它也經常被副詞的限定，如相當確定 或 非?？隙ā?/i> 據(jù)以前的調查，多數(shù)用法專題使用小組成員接受這一結構
例句：
Nothing could be more certain.
沒有比這更確定的了