—Mr. Gao went to Shanghai for the art exhibition last week.

—Is that why he had two days _____?[ ]

A. away          

B. on              

C. of            

D. off

确诊胃、十二指肠急性穿孔最可靠的指标是（）

A．板状腹

B．肠鸣音消失

C．肝浊音界缩小

D．休克

E．X光见膈下游离气体