"When it comes to the Earth, there is no time to waste," says the Earth Day Network. And that is right. {#blank#}1{#/blank#} (protect) our environment is very important. World Earth Day {#blank#}2{#/blank#} (create) in 1970 to ask more people to protect our environment. On April 22 of each year, people around the world celebrate Earth Day.

    Every year there is a special topic, and in 2016 it was "Trees for the Earth''，{#blank#}3{#/blank#} Earth Day that year was all about planting trees. They planned to plant 7. 8 billion trees within the next five years.

    That's a big goal, and you might wonder why{#blank#}4{#/blank#} (tree) are so important. Because they can take in carbon dioxide(CO₂) and improve the air quality(质量). CO₂ is an element(成分) in our atmosphere, but humans make too much of it. {#blank#}5{#/blank#} person makes about 2.3 tons a year, which is bad for the environment.

    Planting new trees is important because people cut down a huge number of trees. Last year, there were 3 trillion trees in {#blank#}6{#/blank#} world, about 139 billion in China. But according to China Daily, the world's total number has been almost cut in half since human civilization(文明) began.

That's {#blank#}7{#/blank#} 15 billion trees are cut down every year.

    So we need {#blank#}8{#/blank#} (plant) more to make up for (弥补) those we lost. One tree can take in 21. 8 kilograms of CO₂ per year. And it's still one of {#blank#}9{#/blank#} (cheap) and best ways to get rid of CO₂.

    But don't forget that we can also help protect the environment by {#blank#}10{#/blank#} (cut) down on the energy(能源) we use every day. Every little thing helps.