急性梗阻性化脓性胆管炎最常见的梗阻因素为()
A.肿瘤或肿瘤压迫
B.结石、蛔虫
C.胆管狭窄
D.慢性胰腺炎
E.胆肠内引流后吻合口狭窄
参考答案:B
Do you think it's important____ for teenagers? [ ]
A. exercising
B. exercise
C. to exercise
属于模糊性反馈行为的是()
A.点头
B.摇头
C.微笑
D.沉默
E.插入"是吗""哦"等语言