Identify the grammatical error in the sentence: 'He left the room quickly, not knowing that the teacher was watching.'
Q1. Identify the grammatical error in the sentence: 'He left the room quickly, not knowing that the teacher was watching.'
Answer: not knowing
Explanation: 'Knowing' is correct; 'not knowing' creates dangling participle error. MDCAT and USAT English reward precise grammar and vocabulary usage.