occur有发生;存在于;等意思，那么你知道occur的过去式是什么吗?今天一起来学习一下occur的过去式以及occur的用法和例句，希望对大家的学习有所帮助!
occur的过去式及其它时态
occur的过去式:occurred
occur过去分词:occurred
occur现在分词:occurring
occur第三人称单数:occurs
occur的用法和例句
1、By noticing these changes, the woman can tell when ovulation is about to occur.
女性通过留心这些变化就能判断排卵的日期。
2、If these drugs are stopped abruptly then some withdrawal symptoms may occur.
如果突然停服这些药，则可能出现一些戒断症状。
3、Emergency cooling systems could fail and a reactor meltdown could occur.
紧急冷却系统有可能失灵，核反应堆有可能发生堆芯熔毁。
4、Didn't it occur to you to close the window?
难道你没有想到去关窗户 吗 ?
5、Opportunities for learning occur spontaneously every day.
学习的机会每天都会自然而然地出现.
6、Three vacations occur in the course of the year, viz, two weeks at Christmas, ten days at Easter and the usual two months in summer.
一年中有三个假期, 即圣诞节两周, 复活节十天以及通常的两个月暑假.
7、Food shortages often occur in time of war.
在战争期间常常发生粮食短缺的情形.
8、Misprints occur on every page.
每一面都有印刷错误.
9、about two in every five epileptic fits occur during sleep.
每5例癫痫病中约有两例是在睡眠过程中发作的。
10、When vacancies occur, the office puts out feelers to the universities.
有空缺职位的时候，办事处就到各个大学去打探。
