在There is always something happening.这句话中happen为什么要加ing

在There is always something happening.这句话中happen为什么要加ing 英语翻译There is always something happening(为什么最后的happen要加ing?) I didn t know what was happening outside这句话中为什么happen加ing? there is always something happening这是英语书上的一句话,happenning是进行时 【急!】关于There's always something happening There is always something out there to discover.这句话中out ther There is something happening in the street 和 There is always there is always something good that comes out of it.这句话为什么用T there is no credible path to stabilising,这句话中为什么加ing呢,不是直接动词 这句话中do为什么要加ing? something interesting happening/happen/happened/happens Thank you for your helping me.在这句话中help为什么加ing?