occur/occurrence

occur /əˈkə:/ vi. (occurred /-d/; occurring /-riŋ/) 1. 发生：At the beginning of August an event occurred. 八月初发生了一个事件。Several fires (storms) have occurred.发生了几次火灾(暴风雨)。 2. (某想法)出现在脑中；出现，存在：A good idea occurred to me. 我想出了一个好主意。It didn’t occur to me that you would object. 我没想到你会反对。It did not occur to me to mention it.我没有想到要提那件事。Misprints occur on every page. 每一页上都有印刷错误。

［辨析］与emerge, appear和happen辨见emerge

 occurrence /əˈkʌrəns/ n. ［u］发生;［c］发生的事: take measures to guarantee against the occurrence of similar incidents in the future 采取措施确保将来不发生类似事件 His arrival was an unexpected occurrence. 他的来到是件意想不到的事情。