人体最硬的组织是（）
A.牙釉质
B.牙本质
C.牙骨质
D.固有牙槽骨
E.骨骼
参考答案：A
肛裂“三联症”包括（）
A.直肠息肉
B.肥大的肛 * *
C.前哨痔
D.肛裂
E.肛瘘
--Do you think that we should prepare for our exam in advance?
-- Of course. _________.
A．Actions speak louder than words
B．Better late than never
C．A good beginning is half done
D．The early bird catches the worm(虫)
