老年人发生机械性肠梗阻时,首先应想到()
A.蛔虫团所致的肠梗阻
B.粘连所致的肠梗阻
C.嵌顿性腹外疝
D.肿瘤
E.小肠扭转
参考答案:D
He looked when he saw a truck coming to him. [ ]
A. scared
B. worried
C. strange
D. sad
在储油罐及周围动火作业,必须办理(),并采取相应的安全措施。