牙冠与牙根交界处的弧形曲线为（）
A.牙冠
B.牙根
C.牙颈
D.牙周膜
E.牙槽骨
参考答案：C
解析：牙槽骨基本依赖包裹它的牙龈组织来供养。
用动词的正确形式填空，词数不限。
小题1:I’d like (go) to the cinema because there is a new 3D film.
小题2:— (be) there two pens in your pencil case?
—No, there is only one pencil in it.
小题3:Kate’s mother (teach) English in No. 3 Middle school in Nanjing.
小题4:My classmates (not watch) TV every day. They only watch it once a week.
小题5:—Thank you for (show) me around your school. —It’s my pleasure.
宋太祖对中国古代政治制度建设作出的最主要贡献是（）
A.实现了国家的大统一
B.建立了完备的监察制度
C.削夺了地方节度使的兵权
D.较好地解决了中央和地方的矛盾
