关于鼻窦的描述正确的是()。
A.是鼻腔周围颅骨与面骨内的含气空腔
B.一般左右对称共有8个鼻窦
C.都有自然窦口与鼻腔相通
D.可分为前后两组
E.以上均正确
参考答案:E
If you insist on smoking heavily like that, you will have to suffer the ________ sooner or later.[ ]
A. achievements
B. causes
C. consequences
D. exchanges
装药空囊