阅读下列短文，从每题所给的A、B、C和D项中，选出最佳选项
Every year on April 22, the world celebrates Earth Day. It's a day that reminds people to protect our Earth, and it is a special day that celebrates the earth as well.
Earth Day was first celebrated on April 22, 1970, in San Francisco, California. Every year, over 100 different countries join together in the celebration of Earth Day. It is the largest, most celebrated environmental event around the world. On Earth Day, we remember nature and learn ways to protect our environment.
What Earth Day is all about is learning about and protecting our planet. People all over the world celebrate our efforts to protect plants and animals and to clean up the world we live in.
We can do lots of things for the earth. Here are some ideas to keep in mind.
*Recycle cans, bottles, and paper. Save them at home and at school, and help your family recycle them.
*Ride your bike or walk to school to keep the air clean.
*Use both sides of your paper at school and at home.
*Turn off the TV when you've finished watching it.
*Don't leave the water running while you brush your teeth.
*Turn off the lights when you leave the room.
And remember, don't ever think you're not important to our earth. You are! That's because Earth Day reminds us that we all share the same planet. Sharing Earth means that taking responsibility for what we use and how we use it. It is a day to think of the environmental changes we face and how to solve them. Protecting Earth is every person's and every country's responsibility.