急性脓胸最常继发于

A．肺部感染

B．胸部开放性损伤

C．膈下脓肿

D．脓毒血症

E．胸外科手术后

—          do you surf on the Internet?

—Once every week. I watch some latest news and chat with my pals there.

A．When

B．How long

C．How often

D．What time