Last month I travelled across the Sahara Desert by          camel with some locals. What      amazing experience!

A．the, an

B．a, /

C．/ , the

D．/ , an

主动脉瓣关闭不全的典型X线表现（）

A.烧瓶心

B.靴形心

C.心影正常或缩小

D.梨形心

E.全心大