一物质系统从外界吸收一定的热量,则( )。
A.系统的内能可能增加,也可能减少或保持不变
B.系统的内能一定保持不变
C.系统的内能一定减少
D.系统的内能一定增加
参考答案:A
A.
B.
D.
根据各组对话内容,从下面方框里提供的5个选项中选出最佳选项
A: I’m sorry to have kept you waiting for so long.B: () I’ve been killing time by listening to music.
A.Sure. What is it
B.It’s very nice of you to say so.
C.It’s nothing.
D.Have a nice trip!
E.Certainly. Here you are.