occurrence
/əˈkʌrəns/noun
1- an incident or event发生的事; 事件：
vandalism used to be a rare occurrence.
故意破坏公共财产的行为过去极少发生。
1.1
- mass noun the fact or frequency of something happening发生; 发生频率：
the occurrence of cancer increases with age.
发生癌症的频率随着年龄而增加。
1.2
- mass noun the fact of something existing or being found in a place or under a particular set of conditions存在; 出现：
the occurrence of natural gas fields.
天然气田的出现。
词源
mid 16th cent.: probably from the plural of archaic occurrent, in the same sense, via French from Latin occurrent- 'befalling', from the verb occurrere （see OCCUR）.