冰箱出现之前人们如何让食物保鲜?
蒋嘉伊杨
Can you imagine life before? It was not so good as life today. Your parents or grandparents probably remember life of that time. When they were kids, some might not have played video games. But what about all the other things? We often do not think about them carefully. Here’s an example:Try to imagine the world before refrigerators.