Think about the different ways that people use the wind. You can use it to fly a kite or to sail a boat. Wind is one of our cleanest and richest power sources, as well as one of the oldest. Evidence shows that windmills began to be used in the ancient Iran back in the seventh century BC. They were first introduced to Europe during the 1100s, when armies returned from the Middle East with knowledge of using wind power.
For many centuries, people used windmills to grind(磨碎)wheat into flour or pump water from deep underground. When electricity was discovered in the late 1800s, people living in remote areas began to use them to produce electricity. This allowed them to have electric lights and radios. However, by the 1940s when electricity was available to people in almost all areas of the United States, windmills were rarely used.
During the 1970s, people started becoming concerned about the pollution that is created when coal and gas are burned to produce electricity. People realized that the supply of coal and gas would not last forever. Then, wind was rediscovered, though it means higher costs. Today, there is a global movement to supply more and more of our electricity through the use of wind.
From the text we know that windmills _______.

A．were invented by European armies

B．have a history of more than 2,800 years

C．have rarely been used since electricity was discovered

D．used to supply power to radio in remote area

The underlined word in Paragraph 2 probably means________.

A．making something cleaner

B．making something flow freely

C．making something flow in a particular direction

D．making something into small parts

One of the reasons wind was discovered in the 1970s is that_______.

A．it is one of the oldest power sources

B．wind power is cleaner

C．it was cheaper to create energy from wind

D．coal and gas failed to meet the needs

What would the author probably discuss in the paragraph that follows?

A．The global trend towards producing power from wind.

B．The design of wind power plants.

C．The worldwide movement to save energy.

D．The advantages of wind power.