A:x6x2=x3
B:x+yx+y=0
C:xx2=1x
D:2xy24x2y=12
____
下图是秦阳陵虎符,铜铸,中分为二,左右各有十二字铭文:“甲兵之符,右才(即在) ,左才阳陵。”发兵必须左、右半符验合,方能生效。上文“右才(在)”后空缺部分应是
The volunteers ____ to provide Russia World Cup with better service.