she went out to see what A is happening B is happened C was happening D was happened

问题描述:

she went out to see what A is happening B is happened C was happening D was happened
请把理由充分些,

C 主句过去时,从句也用过去进行时
【回答补充】他跑出去,是为了看外面正在发生什么事情,所以用过去进行时.