He usually gets up six o’clock Sundays.A. at; on B. on; at C. at; at

问题补充：

He usually gets up six o’clock Sundays.

A. at; on B. on; at C. at; at

答案：

解析：句意：他经常在周日六点起床。在具体的钟点前介词用at；在星期前介词用on；故选A。