英語にして下さい
3年前に拾ってきた猫です。一生懸命に育ててます。
This is a cat which I found three years ago. I've been really taking care of it. (This is a cat I found three years ago.も可) 注:3年前に拾ってきた猫です。猫の名前はタマです。一生懸命に育ててます。 なら、His name is Tama. I've been taking care of him. と人称代名詞を使えます。
I sheltered this cat three years ago. I have been taking good care of it since.
I helped this cat three years ago. (It was left alone..) I take good care of this cat!!!