緊急!!!有無人可以幫我改吓篇文~~~~呢篇文係介紹我暑假果陣時去左九寨溝,寫得5係好好,請多多指教(有3題)

This holiday,I went to Jiuzhaigou and Huanglong.People said that if there should be wonderlands on the earth,Jiuzhaigou Valley must be one of them.Its name is due to the existence of nine stockaded villages of Tibetan origin.
SHOULD BE:
This holiday,I went to Jiuzhaigou and Huanglong.People said that there should be the wonderlands on the earth,Jiuzhaigou Valley must be one of them.Its name i due to the existence of nine stockaded villages of Tibetan origin.

(2nd sentence).....that if there should be wonderlands on the earth, Jiuzhaigou Valley must be one of them.....
-->that if there are some wonderlands on the Earth, then Jiuzhaigou Valley will be one of the wonderlands.
(last sentence)Its name is due to the existence of nine stockaded villages of Tibetan origin.
-->the reason why it is named "Jiuzhaigou" was because the existence of mine stockading villages of Tibetan origin.