2012年12月大学英语六级阅读专项练习题17

1．What is the topic of the passage?
2．Where was ice used after the Civil War?
3．What was essential to a science of refrigeration according to the passage?
4．It can be inferred from the passage that the theoretical foundation of ice box should be that____________.
5．Without an ice box，farmers had to go to the market at night because_______.