For thousands of years, people farmed the land. They grew fruits and vegetables. They hunted and fished for meat. They1cloth, dyes(染料) and paper from plants. They used stone and metal for weapons and tools.
People progressed to making machines powered 2water and steam(蒸汽), and even later, by coal, oil, and petrol. Large cities were built. Factories3of machines created jobs in the cities for thousands of people. The Industrial Revolution(工业革命) changed the lives of many people because, for the first time, more people lived in cities than on 4. Companies built power plants(工厂) to make5to run the machines, factories and cities.
People did not realize these activities were6the Earth. They didn't realize bow7oil, gas, coal and minerals were being used up. 8cities grew bigger and spread across the land, plants and animals began to disappear. Their nature homes were destroyed(破坏) as people moved into new places.
As time passed, people began to 9 the need to protect the Earth and its natural resources(资源). They saw that plants and animals needed protection, so they wouldn't disappear forever. People joined together to tell10around the world to conserve(节约) our natural resources and care for the Earth. And so. Earth Day was born. Each year, more and more people take part in Earth Day. What can you do to help?
