Do not go into the house without the owner's permission.
Today is my Birthday!!!
Before people discover how to farm, they have formed a hunting-gathering way of life. But sometimes they couldn't find enough food to gain weight, and they don't have any civilization, spare time to do other things or a writing system.
I will trade 12 books for 10 packs of berries.
I thought we agree on 15 books for 10 packs of berries!
After people discovered how to farm, they build a more permanent house, since they don't have to move to find more food anymore.
Your books are so old and most of them are poorly written. My berries are fresh, I picked them out this morning. This deal is not fair at all!
After civilization starts forming, people start to create writing systems, they now have writings that help them record rules, important dates, trading agreements, accounting, and etc.
After people dicover how to farm, they have a food surplus, then they formed a trading system, whih help to grow an economy.
After the trading system was formed, people also formed a government, which help them deal with conflicts, which creates laws.
Books mean knowledge. Knowledge could bring you more food. This deal is fair!
Because people know how to farm, there is surplus with food, which makes a diversion of labor, which means more time for people to study other things.