Complex sentence: The prize is a trip to see the first showing of Leonardo Da Vinci's Mona Lisa in Britain for Clyde and his class but Sarah Jane Smith is unaware of this as she and Luke have argued over the untidiness of his room.
Split into simpler sentences: The prize is a trip to see the first showing of Leonardo Da Vinci's Mona Lisa in Britain for Clyde and his class. But Sarah Jane Smith is unaware of this as she and Luke have argued over the untidiness of his room.