Задание 39 ЕГЭ по английскому языку

The Stone Age man used natural glass. He found it by chance. He used it to make weapons, ornaments and money. Then people learned to produce glass. We don't know much about how it happened. They say that Africa was may be one of the original centers to make glass. Ancient traders sold glass in the Mediterranean countries. Egypt was one more country where people could make glass at an early time. The first glass object was created around 3500 BC in Egypt. We know for sure that this industry was very popular in Egypt. The Egyptians learned to press glass into molds. In the 15 century local craftsmen discovered how to blow glass. Before that, glass was very expensive. Only really wealthy people could buy glass. Thanks to this invention, everyone could afford it. Egypt produced a lot of glass things. We can still see some of them in museums.