occurvi.发生;存在;出现;想到
occur and development发生和发展
Occurring by chance.偶然发生的
occur from time to time时有发生
occurring area forecast落区预报
occuring intermittently间歇地发生
Occur for the first time前无此例,事情头回出现
Occurring characteristic发生特点
occurring twice a week.一个星期发生两次的。
occurremce and harmfulness发生危害
Occurring one after anther相继发生