the bell rang at 9 o'clock(改成否定句.一般疑问句.特殊疑问句)

问题描述:

the bell rang at 9 o'clock(改成否定句.一般疑问句.特殊疑问句)

The bell didn't ring at 9 o'clock.
Did the bell ring at 9 o'clock?
When/ What time did the bell ring