Complex sentence: He also has an argument with Henri about why he did what he did, saying he wanted a normal life.He returns to the school to find Sarah after realising the Mogadorians are on their way to kill him.
Split into simpler sentences: He also has an argument with Henri about why he did what he did, saying he wanted a normal life. John returns to the school to find Sarah after realising the Mogadorians are on their way to kill him.