腕管内受到挤压、摩擦的神经是（）
A.骨间掌侧神经
B.正中神经
C.尺神经
D.桡神经
参考答案：B
I am delighted _____ as chairman of the students' union last winter. [ ]
A. to appoint
B. to be appointed
C. to have appointed
D. to have been appointed
WDM技术具有以下特点（）。
A.超大容量
B.对数据的透明传输
C.系统升级时能最大限度地保护已有投资
D.可兼容全光交换
