_____ in the leg, the bird let out a cry of pain asking for help.

A．Being shot

B．Having been shot

C．To be shot

D．Shooting

车辆实行定期检修，并逐步扩大实施状态修、换件修和主要零部件的专业化集中修。客车和特种用途车实行以走行（）为主、（）为辅的计划预防修。