拙政园留听阁内有雕镂蟠龙图案的楠木飞罩，蟠龙昂首，栩栩如生，此为（）时期的遗物。
参考答案：太平天国
Mary often goes to school by bus but _______ her father drives her to school. [ ]
A. sometimes
B. some times
C. sometime
D. some time
渗沟是由（）组成。
A、碎、卵石层
B、反滤层
C、封闭层
D、盖板
