阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式
It seems that Chinese people have always loved to discuss ____ differences between northerners and southerners. Now, another difference has drawn wide attention: the way northerners and southerners shop for food at markets.
People from southern China normally buy ____they need for just one or two meals at a time. It's normal for them to buy just half a Chinese cabbage, two ____（potato）and 25 grams of beef at a time, ____， a person may be laughed at if they do this in the north. Instead, buying enough vegetables and meat for a week ____（be）normal.
The difference could be because ____the different climates. Food can ____（keep）for a long time in the north, as it's ____（usual）cold and dry there. Many northerners have the habit of ____（store）food for a long time. But due to the hot and wet weather in the south, southern Chinese people prefer ____（buy）just enough food for one meal or one day. Otherwise, the food may go bad.
Maybe these debates about different customs help us to understand each other better.
