Please go and see what_____(happen)in the next room.(填写所给词的适当形式并说明)

问题描述:

Please go and see what_____(happen)in the next room.(填写所给词的适当形式并说明)

is happening为什么去隔壁房间看看,发生了什么事?根据意思,事情是正在发生的