眶底爆折眼球陷没的原因是（）
A.眶内脂肪通过"天窗"进入上颌窦
B.眶容积扩大
C.眶内脂肪坏死吸收
D.眼肌缩短，纤维化
E.上述均正确
参考答案：E
平行四边形的性质有：对角______，对边______，对角线______．
If you have any trouble________the work within the time,please tell me. [ ]
A. to finish
B. finish
C. with finishing
D. finishing
