中国人牙列缺损的常见病因是
A.发育障碍
B.龋病、牙周病
C.颌骨外伤
D.根尖周病
E.遗传因素
参考答案:B
I think she is ________at dancing than singing.
A. better
B.good
C.well
D.best
Correct the mistakes in the passage ___.
A.if there are some
B.if any
C.if some
D.if it is any