从方框中选择恰当的句子补全对话，其中有两项是多余的。

Girl: Let's join a club.  1   

Boy: Oh, I don't know.

Girl: Well, what can you do? Can you play chess?  2   

Boy: No, I can't play chess.

Girl:   3 

Boy: Yes, I do. And I can sing.

Girl: Great !   4   

Boy: No, I can't, but I can play the guitar.

Girl: You can?   5 

Boy: Yes,  I do.

客户张某给某商业银行信贷员小李出示了市科委颁发的获奖证书的复印件，小李据此签署了同意贷款的个人意见，小李的行为明显违反了( )。

A．协助执行

B．授信尽职

C．了解客户

D．公平对待