给我8分钟，我去拯救世界.不到一杯咖啡冷却的时间.为什么是8？因为，...(3)

....
Stevens: Can I have a cup of coffee for a moment?
-Christina: Well, how long does it take you to get a cup of coffee?

Stevens:Well...
Suppose the temperature is...
室内环境温度 ambinet temperature = 20 摄氏度
咖啡冲泡温度 initial temperature =T0 90 摄氏度