单项选择题A.Mark the latest homework assignment.B.Put a cancellation notice on the classroom door.C.Make an appointment with the doctor.D.Return some exams to his students.
单项选择题A.She was asked to lead a group of inexperienced cavers there.B.It was the first cave that she had ever visited.C.Clearly marked trails made it easy to explore.D.She hoped to make a discovery.