certain
certain — adjective
1. feeling sure about something because you have good reasons to think it is true.
feeling sure about something because you have good reasons to think it is true.
Ravi is certain that he locked the front door before leaving for work.
be certain + that-clause for personal conviction
Before the exam, Priya felt certain she had reviewed every chapter.
The firefighters were not certain what started the blaze in the basement.
After checking the directions twice, Amara felt certain of the best route to the theatre.
Are you certain about the time the guests plan to arrive tonight?
文法句型
be certain + that-clause
be certain + wh- word
be certain + of/about + noun
用法筆記
Often used with verbs of feeling such as 'feel', 'be', or 'seem'. The that-clause pattern is the most common in everyday speech.
常見錯誤
2. established as a fact that nobody can reasonably question.
established as a fact that nobody can reasonably question.
It is now certain that the volcano erupted at least three times in the past.
it is certain + that-clause for objective fact
Although nobody saw it happen, one thing is certain: a truck hit the fence.
The cause of the accident is not yet certain and requires further investigation.
It is far from certain whether the old bridge can support heavy lorries.
Historians agree that it is certain the battle took place near this riverbank.
- undisputed
stronger, implies no one challenges the fact
- indisputable
more formal and emphatic
- unquestionable
focuses on the impossibility of doubt
- clear
less formal, common in everyday contexts
文法句型
it is certain + that-clause
something is certain
用法筆記
Distinguish from sense 1: here the speaker is stating that something is objectively undisputed, not expressing a personal feeling. Frequently occurs in the impersonal pattern 'it is certain that…'.
常見錯誤
3. so sure to happen that you cannot stop or avoid it.
so sure to happen that you cannot stop or avoid it.
If you do not water the tomato plants, they are certain to die within days.
be certain + to-infinitive for inevitable result
The Tigers are certain to reach the finals after this season's unbeaten run.
With those black clouds gathering overhead, rain is certain before evening.
Theo knew that Gran's arrival was certain to bring laughter into the room.
It is almost certain that the school will close for at least two more weeks.
- unlikely
opposite probability level
- improbable
more formal
文法句型
be certain + to-infinitive
be certain + that-clause
用法筆記
The to-infinitive pattern ('be certain to do') is the most frequent. Do not confuse with sense 1: 'He is certain to win' means winning is inevitable; 'He is certain that he will win' expresses his personal confidence.
常見錯誤
4. used before a person's name when you have named them but the listener does not k
used before a person's name when you have named them but the listener does not know who they are.
A certain Dr. Okafor from the university called while you were out.
a certain + title + name for unknown person
The letter was signed by a certain Ms. Leila Chen whom I had never met.
A certain Mr. Yusuf is waiting for you in the hotel lobby.
The prize went to a certain Beatriz Oliveira from a small town in Brazil.
- some
more informal and dismissive ('some guy named Tom')
文法句型
a certain + name
用法筆記
Always appears before a personal name with the indefinite article 'a'. The tone often suggests the speaker has little or no personal knowledge of the person named.
5. present to a noticeable but not very large degree.
present to a noticeable but not very large degree.
The work requires a certain level of skill with computer software.
a certain level/degree of + uncountable noun
Hana felt a certain sadness as she said goodbye to her childhood home.
a certain + abstract emotion noun
There is a certain amount of risk in any new business venture.
The old house has a certain charm that is hard to describe in words.
The recipe calls for a certain amount of sugar, but you can adjust it.
- some
less formal and vaguer
- a measure of
more formal, literary
文法句型
a certain + noun
a certain amount/degree of + noun
用法筆記
Often used with abstract nouns (sadness, charm, appeal, risk) or quantity nouns (amount, level, degree). The emphasis is on the vagueness or the difficulty of being more precise.
certain — determiner
1. referring to a specific person, thing, or group without identifying them more ex
referring to a specific person, thing, or group without identifying them more exactly.
Certain members of the club have already paid their yearly fees.
certain + plural noun for unspecified group
There are certain rules that every guest must follow during the stay.
In certain cultures, removing your shoes before entering a home is required.
The nurse explained that certain foods can trigger a serious allergic reaction.
Under certain conditions, the experiment produces surprising results every time.
- particular
slightly more formal and explicit about specificity
- specific
emphasises exact identity
文法句型
certain + plural noun
certain + uncountable noun
用法筆記
Use this when you want to specify that you mean some items within a group but it is not necessary or possible to list them all. Do not confuse with the adjective sense 4 (NAMED), which is used before a specific person's name.
常見錯誤
2. used when putting a precise number or description on something is difficult or u
used when putting a precise number or description on something is difficult or unnecessary.
The repairs will cost a certain amount that we have not yet worked out.
a certain amount of + vague quantity
There is a certain beauty in the way the old stone walls line the lane.
The director spoke with a certain authority that made everyone listen closely.
This neighbourhood has a certain charm that appeals to artists and musicians.
Kofi felt a certain unease as he walked through the dark parking garage alone.
- some
shorter and less formal, but may sound too vague
- a degree of
more formal, focused on measurable extent
文法句型
a certain + noun
a certain + adjective + noun
用法筆記
Distinguish from determiner sense 1: sense 1 picks out a specific subset ('certain members', 'certain foods'), whereas this sense describes a vague quality or quantity of a single thing ('a certain charm', 'a certain amount').
certain — pronoun
1. a small number of people or things belonging to a larger group, without naming t
a small number of people or things belonging to a larger group, without naming them.
Certain of the employees expressed concerns about the new working hours.
certain of + the + plural noun
Certain of the paintings in the gallery were damaged during the flood.
Certain of his arguments were hard to follow without a science background.
Certain of the guests arrived late because of the heavy snowfall on the roads.
文法句型
certain of + plural noun/pronoun
certain + of + determiner + noun
用法筆記
This is a formal construction, most common in written English. In everyday speech, 'some of the…' is used instead. Always takes a plural verb.