===CORRECTIONS===

Daine: Cat can jump but dogs cant jump.
Correct: Cats can jump but dogs can't.
Explanation: Be consistent with the use of your nouns so if it is plural others should be in its plural form. You should also avoid repetition of words to make the sentence simple.

Daine Dogs are very playful because they like to excersise.
Correct: Dogs are very playful because they like to excercise.
Explanation: Be careful with your word spellings.

Daine: Fish is very yummy and also cat likes to eat also.
Correct: Fish is very yummy and cats like it too.
Explanation: Make the word cat in its plural form since e are generalizing that cats like fish as humans do.

Daine: I can run very quickley because at our school I am third fast runist.
Correct: I can run very quickly because at our school I won third place as a runner.
Explanation: Be careful with your word spellings. Make your sentences shorter and clearer to understand.