### Chinese: 它们强度很低，球打到拍子上面，振动非常大，硬球顶不住，高手都很难驾驭。
### English: They are very low in <v>intensity</v>, the ball hits the racket, the vibration is very large, the hard ball can't stand it, and it is difficult for the masters to control it.
### Errors: There is a minor style/awkward error at "intensity" within <v></v>.

### Improved English: They are low in strength, and there will be too much vibration when the ball hits on it; it cannot withstand hard balls, and even professional cannot handle it.
