题目

--- How about the book you are reading?     --- Good indeed. It_____ many problems we have come across in our study.     A. says   B. talks    C. covers          D. refers   答案：C如果一个反应的△H－T△S值为零，则此反应A．处于平衡状态B．是放热反应C．不进行D．能自发进行