—I find it very difficult to read ________ novel you lent me last week.

—Yes.It's necessary to have ________ good knowledge of history.

A．the；/

B．a；/

C．the；a

D．a；a

下述哪种情况应考虑消化性溃疡发生后壁慢性穿孔

A．突然剧烈腹痛

B．全腹肌紧张呈板状

C．膈下游离气体

D．病人处于休克状态

E．腹痛顽固而持续