AN alleged thief stunned a magistrate yesterday by asking: 'What is a trial?' Ng Chun-sum, 25, from the mainland, had been told his trial would take place on January 2. An interpreter said: 'He asks 'What is a trial?'' Eastern Court magistrate William Eccleton told Ng: 'The trial date is when the police officers will give evidence as to what they say happened. That's it.' Ng is accused of stealing a bag containing $1,634 cash, keys and an ID card from Tuen Li-chen who left her bag unattended outside the Tanner Hill Police Married Quarters, North Point, on Friday. Ng was visiting his sister-in-law, a cleaner at the quarters.