— Have you been here before?

— Yes. This is the third time that I ______ to Shanghai.

A．come

B．came

C．have come

D．had come

男性，22岁。手枪子弹射中左股根部2天。体检发现伤口红肿，有少许脓性分泌物，且子弹只有入口没有出口。应采取的治疗措施是

A．立即取出子弹

B．清创

C．清创缝合

D．引流

E．换药