Today, most of the world’s money is made up of paper. However, the idea of paper money first     1     ( start ) in China. For much of Chinese history,     2     was considered as money were small coins with holes in the middle. These coins were put on a piece of string, 100 coins to a bunch.     3     ( normal ), ten bunches were kept on     4     same string, which could be very heavy to carry around. Since even 1,000 coins were not really worth that much, business deals of any     5     ( important ) could require many strings of coins-even whole rooms of them.

To solve this problem,     6     ( begin ) around the late 8th and early 9th centuries, businessmen would deposit their coins with someone, who would give     7     ( they ) a piece of paper called feiqian, or “ flying money ”. Then when the businessmen did business, he could use that paper instead     8     having to carry a truckload of coins around. In 812, three departments of the Tang government began using paper receipts for large deals where a lot of coins would have to     9     ( carry ) over a long distance. This was not money in the modern sense, as it could only be used     10     ( pick ) up coins at the end of the trip. This finally led to the printing of paper money as we know it today by the early 11th century.

Ocean exploration changed human history

One of humanity’s greatest achievements has been mastering routes across the world’s oceans. Communities separated by thousands of miles     1    (bring) into contact and religious ideas have spread across the waters, while artistic creativity has been motivated by the experience of seeing the products of different civilizations. Customs have been decisively altered by the movement of ships across the oceans. No one drank tea in medieval Europe, but     2     contact had been made with the tea-drinking Chinese, tea became popular with millions of people from Sweden to the United States.

We tend to hold the view     3     the opening of the oceans was the work of the great explorers, especially the 15th century pioneers who edged their way through uncharted waters to southern Africa, the Indian Ocean and the lands of the Indies. These were sailors     4     Christopher Columbus, who chanced upon unsuspected lands that blocked the expected sea route from Europe to China and Japan. But while these men     5     give the Age of Discovery its name, they didn’t start the exploration of the world’s oceans — and there were also scores of merchants who followed in     6     route, taking full advantage of new knowledge about the open ocean to develop trade links across the world,     7     laid the foundation for modern globalization. These were the people who really mastered the oceans and brought the continents into contact.

Since then, the oceans have only continued     8    (tie) the world together — most dramatically when new routes were literally carved out, with the building of the Sues Canal in the 19th century and the opening of the Panama Canal in 1914. The first goods to pass through the Panama Canal consisted of a cargo of     9    (tin) pineapples from Hawaii. The Pacific and the Atlantic were     10    (closely) tied together than ever before.