男性，62岁，因急性化脓性阑尾炎行阑尾切除术后5天，左上腹持续性疼痛，逐渐加重，疼痛放射至左肩部，深呼吸及咳嗽时加重。T 37℃，压痛局限于左季肋下，并有叩击痛。X线检查提示：左膈肌升高；B超：左膈下有5cm×6cm液性暗区。最可能的诊断为

A．化浓性门静脉炎
B．阑尾残端瘘
C．膈下脓肿形成
D．急性胰腺炎
E．左下胸膜炎

This is a process          happens when land becomes desert        people cut down trees and dig up grass.

A．when; because

B．that; because of

C．when; because of

D．which; because