梅尼埃病的主要病理改变是()
A.蜗管扩张膨大
B.球囊扩张膨大
C.膜迷路破裂
D.螺旋器退行性变,血管纹萎缩
E.内淋巴囊之囊壁纤维化
参考答案:A, B, C, D, E
We have ( ) a number of our customers in this area and ninny of them take an interest in your products.
A. contactedB. contacted withC. been contacted withD. in contact with
石油主要由()等元素组成。
A、碳、氧
B、氧、氢
C、碳、氢
D、硫、氢