Complex sentence: He tries to hide himself in a political meeting, but is mistaken for the introductory speaker; he gives a rousing impromptu speech (without knowing a thing about the candidate he is introducing), but is recognised by Pamela, who gives him up once more.
Split into simpler sentences: He tries to hide himself at a political meeting, but is mistaken for the introductory speaker. He gives a rousing impromptu speech--without knowing a thing about the candidate he is introducing--but is recognised by Pamela, who gives him up once more.