原发性三叉神经痛的病因()
A.急性上颌窦炎
B.原因不明
C.多发性硬化
D.延髓空洞症
E.颅底肿瘤
参考答案:B
网上特约商户标识LOGO的电子文件格式为()。
A、TXT
B、JPEG
C、BMP
D、GIF
The man in the corner be Mr. White. He is attending a conference in the City Hall. [ ]
A. mustn't
B. may not
C. needn't
D. can't