—                  ?

—Yes, I' m looking for a pen．

A．What are you doing                            B．What do you want to buy

C．What do you like                                  D．Can I help you

— _________?

—Yes，I'm looking for a pen．

A．Can I help you                                         B．What are you doing?

C．What do you want to buy                           D．What do you like?