As he ______ to his work that he didn't notice that it was already past midnight.    [ ]

A. was so busy  

B. so devoted  

C. was so devoted  

D. was so turned  

下列说法中正确的是 [ ]

A．物体内能增加，可能是从外界吸收了热量

B．流星与空气摩擦生热、发光，内能转化为机械能

C．用保鲜袋装蔬菜放入冰箱，为了减慢液体蒸发

D．在高山上烧水时，90℃水就能沸腾，说明水的沸点与气压有关