腹部反跳痛的发生机制是（）
A.肠腔胀气
B.内脏肿大、充血
C.肿瘤淋巴结转移
D.炎症波及腹膜壁层
E.胆管结石并梗阻
参考答案：D
The student________from the training so much that he was________the first prize in the event. [ ]
A. benefited; benefited
B. awarded; awarded
C. awarded; benefited
D. benefited; awarded
( )必须为从事危险作业的职工办理意外伤害保险，并为施工场地内人员生命财产和施工机械设备办理保险。
A．发包人
B．承包人
C．劳务分包人
D．以上三者均有可能
