说出US的功能。
参考答案：US是多功能操作站，具有人机接口功能。
Kangkang likes watching TV, but his mother doesn't let him _____ TV on school days. [ ]
A. watching
B. watch
C. watches
D. watched
无牙颌的上颌隆凸，上颌结节，颧突，切牙乳突区属于
A．主承托区 B．副承托区 C．缓冲区 D．边缘封闭区 E．固位区
