—If you    _ a new idea, please call me as soon as possible.        

—Sure,I will.        [ ]

A. keep up with          

B. catch up with        

C. feed up with          

D. come up with

A、B、C三个轻质小球。已知A带负电。A和B互相吸引，C和A互相排斥，则    [ ]

A．B一定带正电，C带负电   

B．B可能不带电，C带负电

C．B可能带正电，C带正电    

D．B一定不带电，C带正电