The man was just about to stand up ____ someone sat on the edge of his overcoat.   [ ]

A. while    

B. suddenly    

C. as    

D. when

用一个杯子盛满水向一个空罐里倒水。如果倒进2杯水，连罐共重0.6千克；如果倒进5杯水，连罐共重0.975千克。这个空罐重( )千克

A．0.35

B．0.45

C．0.375

D．0.25