—Your room is in a mess, David.
—I'm sorry. I'll __________ right now.
A:pick up
B:clean it up
C:clean up it
D:turn it up
南宋时有“国家根本,仰给东南”“苏湖熟,天下足”的说法,这表明宋代( )
有一个数值转换器,原理如下:当输入的x为64时,输出的y是( )