Complex sentence: While talking in the middle of the street, Shax appears and attacks the two of them, but Piper blows him up, thinking he is dead, both Prue and Piper are confused because if there's a spell in the book, they normally need it.
Split into simpler sentences: While talking in the middle of the street, Shax appears and attacks the two of them, but Piper blows him up. Thinking he is dead, both Prue and Piper are confused because if there is a spell in the book, they normally need it.