【急!】关于There's always something happening

【急!】关于There's always something happening there's always something about There is something happening in the street 和 There is always there is always something happening这是英语书上的一句话,happenning是进行时 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?) What's happening there There's always something h________ in the mall. there s always something h but nobody knows the reason 改定语从句 There's always something happing There's something gone,it always comes back,but there's some there are always some traffic accidents happening easily whe