单项选择题A．They are few in numbers.B．They depict important historical events.C．They provide a lot of information about ordinary people.D．They conceal clues about the social role of artists.

单项选择题A．There were more runners in the marathon than last year.B．It was the first time for Mike to participate in the marathon.C．Mike was quite disappointed with his performance.D．Mike will join in the marathon again next year, and he believes he will do better.