手术切断后会导致肛门失禁的组织是
A．外括约肌皮下部B．外括约肌浅部C．外括约肌深部D．内括约肌E．肛管直肠环
参考答案：E
—Can you go to the Science Museum with me tomorrow?
— _____ But I have to study for my math test.[ ]
A. That's all right
B. I'd love to
C. Of course not
D. Never mind
为何氢冷发电机机内氢气纯度要高于96％？
