工程实践表明，炮眼利用率随炮头移向装药底部而增加，反向起爆的效果优于（）。
参考答案：正向起爆
The number of giant pandas is getting _____ because their living areas are becoming farmlands. [ ]
A. less and less
B. larger and larger
C. smaller and smaller
D. fewer and fewer
胆道感染急性并发症不包括
A．胆囊穿孔
B．胆道出血
C．胆管炎性狭窄
D．胆源性肝脓肿
E．胆源性胰腺炎
