— Look!  Somebody ________ the sofa.

— Well, it wasn't me. I didn't do it.       [ ]

A. is cleaning        

B. was cleaning      

C. has cleaned        

D. had cleaned

2008年9月16日,中国人民银行下调人民币贷款基准利率,并下调中小金融机构人民币存款准备金率1个百分点。这表明中国人民银行具有        的职能。   

A．发行人民币，管理人民币流通

B．依法制定和实施货币政策

C．经理国库

D．持有管理国家外汇储备、黄金储备的职能