Conversation so far:
How was Seung-Hui Cho's behavior in school?
Cho looked down and refused to speak when called upon. After one teacher threatened to fail Cho for not participating, he began reading in a strange, deep voice.
How did the bullying at Westfield High School effect Seung-Hui Cho?
Cho looked down and refused to speak when called upon. After one teacher threatened to fail Cho for not participating, he began reading in a strange, deep voice.
Was Seung-Hui Cho a bad student because of his anger?
Cho looked down and refused to speak when called upon.

Question: What was done when he refused to speak?
Self-contained rewrite: What was done when Seung-Hui Cho refused to speak when called upon?