坏疽胆囊炎并发胆囊穿孔，多发生在
A．颈上部B．峡部C．底部D．前部
参考答案：C
I hope that ____ I have been able to do does good to them all. [ ]
A. which
B. what
C. that
D. when
焦-片距增大一倍，X线胶片感光量相应()
A．增加1／Z倍
B．增加1／4倍
C．增加1／8倍
D．减少至1／2
E．减少至1／4
