核心畫面
Think of the noun form of 'something happened': you can point either at the event itself — one thing that took place, countable, one of several — or at the bare fact that it took place at all, and how often. Both readings are formal; in everyday speech people just say 'something that happens' or 'how often it happens'.
可以想成把「發生了一件事」變成名詞之後的兩種指法：一種是指向那件事本身（一件發生過的事，可以數，可以說第一次、第二次…更多收起
可以想成把「發生了一件事」變成名詞之後的兩種指法：一種是指向那件事本身（一件發生過的事，可以數，可以說第一次、第二次），另一種是指向「它發生了」這個事實，以及發生得多頻繁。兩種都偏書面、正式；日常講話多半直接說 something that happens 或 how often it happens。原始詞典資料2 筆記錄
以下是外部詞典記錄的用法，原文照列，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
occurrencenoun/əˈkʌɹ.əns/
- 1
An actual instance when a situation occurs; an event or happening.
- Since the mid-1980s, when Indonesia first began to clear its bountiful forests on an industrial scale in favour of lucrative palm-oil plantations, “haze” has become an almost annual occurrence in South-East Asia. The cheapest way to clear logged woodland is to burn it, producing an acrid cloud of foul white smoke that, carried by the wind, can cover hundreds, or even thousands, of square miles.
- 2
grammarhuman-scienceslinguisticsThe lexical aspect (aktionsart) of verbs or predicates that change in or over time.
- The time interval of an occurrence—a temporal instantiation—is a single occasion. However, a series of such occasions can fall within a certain time interval; in this case we may represent the occurrence as a single situation (cf. I ran off and on for an hour, I ran and ran for an hour, I would run and then run some more).
- The most basic Aktionsart distinction is between states and occurrences. […]Based on consideration of inherent differences between the events involved, Vendler distinguished three different types of occurrence, achievements, activities, and accomplishments.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。