A:内外服制
B:分封制
C:宗法制
D:礼乐制
—I'm sorry.I didn't catch the early bus and I had to _____ the next one.
You're supposed ______ your room up before you go out.
一支篮球队准备购买10双运动鞋,各种尺码统计如下表:则这10双运动鞋尺码的众数和中位数分别为( )
人是生态系统中的生产者.(判断对错)