牙骨质增生是由于增生的牙骨质沿牙根不断沉淀，使牙根（）
A.密度减低
B.密度不均匀增高
C.变粗增大
D.变细缩小
参考答案：C
Whenever the teacher was not here,the children make a lot of noise.
A．will
B．would
C．were to
D．were going to
尺码牌底端与POP（）持平。
A．上沿
B．下沿
C．不需
