Hi! My name is Shen Gang. I am a schoolboy. My __小题1:_____ is far from my home. I must__小题2:____ up early in the morning. I usually go to school by bus. Every day it takes(花费) me about half an hour to get there. I have no __小题3:______ for breakfast at home. I often have some bread___小题4:_____ breakfast on my bike. I don’t __小题5:_____ to be late for the morning exercises(早操). I have lunch____小题6:___ school. Sometimes I ___小题7:__ basketball with my classmates after school. I often get __小题8:______at about 5:30 p.m..

下列哪一项不是牙根敏感的原因

A．牙颈部牙骨质薄

B．牙龈退缩

C．牙骨质中有神经分布

D．牙颈部缺乏牙骨质

E．牙周刮治破坏牙骨质