`24.` D

`-` D/c: About three thousand years ago, there were no shops.

`25.` B

`-` D/c: For example, if you needed something to wear, you had to kill an animal and get its coat.

`26.` D

`-` D/c: If you were a good hunter and had a lot of coats, you could exchange them for other things you needed. You could get meat, fruit or an axe. This way of exchanging things is called barter.

`27.` Meat, fruit

`-` D/c: You could get meat, fruit or an axe. This way of exchanging things is called barter. Later on, ....not go bad easily.

`28.` Because they were easier to carry than metal bars.

`-` D/c: After five hundred years later, people began to make coins. They were easier to carry than metal bars.

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`-` coat (n): bộ lông (thú)

`-` exchange (v): thay đổi

`-` tin (n): hộp thiếc

`-` bars (n): thanh, thỏi

`-` discovered (v): đã khám phá

`-` coins (n): đồng xu

`-` metal (n): kim loại

`-` value (n): giá trị

`-` appeared (v): đã xuất hiện