Complex sentence: On the morning of Tommy Pickles' first birthday, Stu and Didi try to feed Tommy with carrot baby food, but he sees a commercial for dog food and decides that he wants to eat it, believing it will turn him into a dog.
Split into simpler sentences: On the morning of Tommy Pickles' first birthday, Stu and Didi tries to feed Tommy with Carrot baby food. But he sees a commercial for dog food and decides that he wants to eat it, believing it will turn him into a dog.