驼峰计算机速度控制系统，一、二部位出口速度控制精度（）以上达到±1.5km/h。

A.80%

B.85%

C.90%

D.95%

Many young people are now crazy about Board Games (桌游), which are based on pure strategy and kind of            of players’ psychological quality.

A．exchange

B．charge

C．challenge

D．preference