二尖瓣狭窄并发心房颤动和右心衰竭时，可在右房形成附壁血栓，而致（）
A.脑栓塞
B.肾栓塞
C.肠系膜栓塞
D.肺栓塞
E.脾栓塞
参考答案：D
In relation to employment law, explain and distinguish between an independent contractor and an employee, who is a servant. (10 marks)
进口可用作原料的废物前，进口单位应事先取得国家质检总局签发的《进口废物批准证书》后方可办理检验检疫。( )
