请问What happens?与What happening?的区别?

请问What happens?与What happening?的区别? What happened与What's happening的区别 what happen与what happens的区别是什么? what happens during lunch time What's happening outside? what's happening 和 what's wrong的区别 what is happening?的happening是什么词性 what happens what was happening?happening词性 “what's the happening ”和“what the happened”的区别是什么啊? What ______ if I drink this?选项:a、happens b、is happening c、wi What's going on 和what happens next两句的区别 "What's happening?"的同义句?