----Have you seen ________ pen? I left it here this morning．

----Is it ____________ black one? I think I saw it somewhere．

  A．a; the                B． the; the                     C．the; a                 D．a; a

—Have you seen         pen? I left it here this morning.

—Is it         black one? I think I saw it somewhere.

       A．a; the                  B．the; the                C．the; a                  D．a; a

— Have you seen______ pen? I left one here this morning.
— Is it___________ black one? I think I saw it somewhere.

A．the; the

B．a; a

C．the; a

D．a; the