occur
verb uk/əˈkɜːr/ us/əˈkɝː/ -rr-
(HAPPEN)
B2 [ I ]（尤指事故及其他意外事件）发生
(especially of accidents and other unexpected events) to happen
An accident involving over ten vehicles has occurred in the east-bound lane. 在东向车道上发生了一起涉及十多辆汽车的交通事故。
If any of these symptoms occur while you are taking the medication, consult your doctor immediately. 服药期间如果产生了这些症状中的任何一种，要立即就医。
- More examples
- Many suicides occur in prisons.
- We are of course investigating how an error like this could have occurred.
- Evolution occurs as a result of adaptation to new environments.
- Evidence suggests that errors may indeed be occurring.
- The partition of India occurred in 1948.
(EXIST)
[ I + adv/prep ]存在；出现
to exist or be present in, among, etc.
Violence of some type seems to occur in every society. 每个社会似乎都会存在某种形式的暴力。
Minerals occur naturally in the earth's crust. 矿物自然存在于地壳中。
Phrasal verb
occur to someone （某人）想到，（想法或主意）出现在（某人）头脑中
If a thought or idea occurs to you, it comes into your mind.
The thought did occur to me. 我确实冒出了这个念头。
[ + that ] It never even occurred to us that he hadn't been invited. 我们压根儿没想到他未被邀请。
Does it ever occur to you that I might want to be on my own sometimes? 你难道从没想过有时候我或许喜欢独处？