common knowledge

1.慣用語B2

釋義

something that is known to most or all members of a group or community — so widely accepted that people consider it unnecessary to explain or prove.

例句

It is common knowledge among the villagers that the old well has been dry for decades.

it + be + common knowledge + among [group] + that-clause

The company's financial troubles became common knowledge when the annual report was leaked.

became common knowledge

同義詞

well-known fact
slightly more formal; often used in academic or journalistic writing
general knowledge
broader in scope — can refer to things learned through education, not just everyday awareness
public knowledge
emphasises availability to the general public rather than a specific community
open secret
implies that something is known despite not being officially acknowledged; slightly informal
widely known fact
more explicit about scope; can sound more formal

反義詞

secret
information deliberately kept from others
mystery
implies something puzzling or unexplained, not merely unknown
inside information
known only to a select few with special access
rumour
unverified information; may or may not be true

文法句型

it + be + common knowledge + that-clause

something + be + common knowledge + (among/in/within) + group

用法筆記

Can range from 'known by everyone in a group' to 'known by most members of a group'. The strength depends on context. Frequently used predicatively with a that-clause ('It is common knowledge that…'). Cannot be preceded by an article ('a common knowledge') because it is an uncountable noun phrase.

常見錯誤

❌It is a common knowledge that the moon orbits the Earth.

✅It is common knowledge that the moon orbits the Earth.

💡'common knowledge' is uncountable and does not take an indefinite article.

❌Common knowledge tells us that smoking is bad for health.

✅It is common knowledge that smoking is bad for health.

💡'common knowledge' is not an agent; it cannot 'tell' us things.

❌The common knowledge among engineers is that the bridge needs repairs.

✅It is common knowledge among engineers that the bridge needs repairs.

💡'common knowledge' typically avoids the definite article even when a prepositional phrase follows.