A:x是弹簧的伸长或压缩后的长度
B:x是弹簧原来的长度
C:x是弹簧伸长的长度或压缩的长度
D:x可以是任意大小的值
-Qin Shu has just beaten Li Hui in our school ping-pong game!
-It's hard to _________ a girl with only one arm can play ping-pong so well!