题目

As we know，Meizhou Island is a famous place of interest in Putian.My pen pal，Sam，from Australia would like to visit it very much.He is coming here for a holiday next week.He is planning to stay here for seven days.He has never been to Putian before，so he needs to know something about it.The weather is the most important thing that he would like to know.He wants to know what he should get ready for the trip and what kinds of clothes he has to take with him.Here is the five－day weather report for Putian.DateWeatherTemperatureJuly 1st27－35℃July 2nd26－33℃July 3rd26－32℃July 4t如图所示，已知R1与R2两端所加电压为24V．如果R1=80Ω，开关闭合后，R2中的电流为0.2A，则R2=    Ω，干路中电流I=    A．再给R1、R2并联一个200Ω的电阻，电路中的总电阻会变    （填“大”或“小”）．