单项选择题
A．Because Dr. Johnson is busy tomorrow. B．Because Dr. Johnson won’ t come to his surgery tomorrow. C．Because Jack is on duty tomorrow. D．Because Jack is busy tomorrow.
A．Manager and clerk. B．Director and secretary. C．Doctor and nurse. D．Professor and student.
A．About a day. B．About two days. C．About a week. D．The speakers don’t tell us.