John thinks it would be long ________ he is ready for his new job.

A．when

B．after

C．before

D．since

诊断慢性阑尾炎，下列哪一项最重要

A．慢性右下腹隐痛史

B．有过典型的急性发作病史

C．右下腹有轻度压痛

D．X线钡餐检查阑尾炎未显影

E．排除阑尾炎以外疾病的可能