单项选择题 Before making your speech, you'd better ________ y

填空题 将等质量的90℃的热水和20℃的冷水混合到一起，假定混合在保温良好的近似绝热条件下进行，且水的热容近似为一常数4．18kJ／(kg.K)。试求混合过程的总熵变化（）。

单项选择题 —Does Bill do his new job well?— ________ his old job. Im afraid theres no hope for him.A. Not better than B. No betterthan C. Not so well as D. Notas well as