Just look at the rain pouring down!

可以理解成：Justlookattherainwhoispouringdown嗎？

還是理解成后置定語呢？

Seventimeshaveidespisedsoul.

為何這里have是倒裝？

Just look at the rain pouring down! （正。目前分詞作賓補）
Just look at the rain who is pouring down. （錯。不要隨意改動句子）
Seven times have I despised my soul. （倒裝句，times 次數開頭引出倒裝）

Seventy times have I told you not to be late.
我不知告訴你過多少次不要遲到。

Many times have I heard this.
我聽這話已經不少次了。