Complex sentence: Miss Hoolie sends him home with a carton of juice, but instead of sitting down and relaxing, Archie decides to build a castle, but it falls down and he gets angry again and he squashes his juice.
Split into simpler sentences: Miss Hoolie sends him home with a carton of juice. But instead of sitting down and relaxing, Archie decides to build a castle, but it falls down and he gets angry again and he squashes his juice.