Complex sentence: One of them jams a tire pump in Dave's wheel, causing him to crash, which leaves him disillusioned and depressed; he subsequently confesses his deception to Katherine, who tearfully slaps him.
Split into simpler sentences: One of them jams a tire pump in Dave's wheel, causing him to crash, which leaves him disillusioned and depressed. He subsequently confesses his deception to Katherine, who tearfully slaps him.