テレビで見た時のことを話したいのですが！
｢テレビでカンガルーと人間が戦ってるのを見て私はカンガルーが強いと思ってなかったからとても驚いたわ！｣

Kangaroo and human were fighting when I watch on Tv,it was so surprised,because I didn’t know Kangarro was strong.

少し難しいですけど訳して下さい。

I saw Kangaroo was fighting with a person on the TV. I didn’t know Kangaroo was strong though that amazed me Kangaroo won the fight.

＞この英文だとカンガルーがその戦いで勝った、それに対してあなたが驚いたってことになりますけど、どうでしょう？ 　

ありがとうございます！レス１さんの文だと迫力！があるって感じします！ 　

When I watched a kangaroo and a human fighting on TV, I was so surprised because I didn’t know that a kangaroo was strong.
(this is ok, but maybe it’s more natural to say, ”When I watched a person fighting with a kangaroo on TV, I was so surprised because I didn’t know kangaroos were strong”) 　

*この文章では分かりませんがカンガルー「１匹」と「１人」の人間が戦っていたと仮定します。
I saw a kangaroo and a person were fighting on the TV. I was really surprised to see the kangaroo won, because I did not know kangaroos were so strong.