betty 
Today is very hot.My sister her hands is hurt.It is very ache.Ruby and I are eat two apples. I study English.Chinese and math.I am very happy.
建議修改為:
It is hot today. My sister hurt her hands and they are aching. Ruby and I ate two apples. I studied English, Chinese and math today. I am very happy.
第二句主詞重複,又是my sister又是her hands, 這兩個要選擇一下,
ache這個字若你有查字典你會知道它不是形容詞而是動詞或名詞,所以不能very ache, 我們今天才說過,妳得用副詞去修飾動詞,並且你前面又有be動詞is, 這樣就重複動詞了,所以正確用法應該為it aches a lot, 但前一句你又用複數hands, 所以應該是they ache a lot, 若當名詞用就是there are a lot of aches, 我把它改為they are aching. 也可以用it is painful代替
Ruby開頭這句重複動詞,看不出你是已經吃了(ate)還是正在吃(are eating),
你今天讀了三個科目,study要用過去式,記得,現在簡單式只用在每天的習慣上或是不變的真理,因為你一開頭就是today, 看的人會直接想說這是你今天的行程,用現在簡單式就會怪怪的,除非你後面加一個everyday之類的把這件事便成一個固定的習慣
這樣懂嗎?不懂再問^^~