The poor boy seems _____ the news that his father died in the car accident for there is no sign of sorrow on his face.

A．not to be known

B．not to have received

C．to have not received

D．not to know

关于间接鼻咽镜检查的描述中，错误的是：（）

A.受检者端坐，咽反射敏感者经口喷用1％丁卡因

B.受检者张口用鼻呼吸

C.受检者左手将舌牵出口外

D.将鼻咽镜加温

E.鼻咽镜镜面向上，置于软腭与咽后壁之间