He is the only one of the students who _____ a winner of scholarship for three years. [ ]

A. is

B. are

C. have been

D. has been

如图是密闭的气缸，外力推动活塞P压缩气体，对缸内气体做功800J，同时气体向外界放热200J，缸内气体的

A.温度升高，内能增加600J

B.温度升高，内能减少200J

C.温度降低，内能增加600J

D.温度降低，内能减少200J