—Where is your PE teacher?          

—Look! Our PE teacher is swimming. He            swimming for exercise.             [ ]

A. can't be                

B. might              

C. must be

为弥补今年的财政赤字，应采取的主要方法是

A．发行国债

B．向商业银行贷款

C．减少开支

D．发行股票