鼻旁窦
参考答案:
是鼻腔周围含有空气的骨性腔洞。(共有四对,对发音起共鸣作用)
It is an unfair thing for our students____ have devoted 12 years to preparing the exam to be beaten by those_____ use illegal methods..
A.who; 不填
B.不填,who
C.who,who
D.不填,不填
牙体组织中来自特化上皮组织的是
A.牙釉质B.牙本质C.牙骨质D.牙髓E.以上均是