YOU SAID:
There are big cats and also small cats
INTO JAPANESE
大きい猫もいるし小さい猫もいる
BACK INTO ENGLISH
There are big cats and there are small cats
INTO JAPANESE
大きな猫もいるし、小さな猫もいる
BACK INTO ENGLISH
There are big cats and there are small cats
That didn't even make that much sense in English.