what a relief it was when the boulders suddently disappearanced

what
a
relief
it
was
when
the
boulders
suddently
disappearanced！
what
a
relief
it
was是主句，感叹句式。
when
the
boulders
suddently
disappearanced！
指代it，为主语从句。
当那块大石头消失的时候，那是多么让人觉得轻松啊！

扩展阅读：assessment ... take advantage of ... that is not the case ... i will be back ... congratulation ... you got me there ... what the fack ... be on my own ... how surprising ...