“When it comes to Earth, there's no time to waste, ” says the Earth Day Network. And that is right. Protecting our environment is very important, and World Earth Day was _______ in 1970 to raise people's environmental awareness. On April 22, people around the world _______Earth Day.

Every year there is a special _______, and this year it is “Trees for Earth”, so Earth Day will be all about _______ trees. Their goal is to plant 7. 8 billion trees in the next five years. That's a big goal, and you might wonder _______ trees are so important. Well, for one, they can help stop climate _______. Carbon dioxide(二氧化碳)is a chemical in our atmosphere, but _______ make too much of it. Each person makes about 2. 3 tons a year, which is _______ for the environment.

Well, guess what? Trees _______ carbon dioxide and protect the air quality. Planting new trees is important because people cut down __________ trees. Last year, there were 3 trillion(万亿)trees in the __________, about 139 billion in China. But according to Time, the world's total number has been __________ cut in half since human civilization(文明)began. That's because 15 billion trees are cut down every year.

So we need to __________ more to replenish(补充)the ones we've lost. One tree can take in 48 pounds (14 kg)of carbon dioxide per year. And it's still one of the cheapest and __________ ways to get rid of carbon dioxide.

But don't forget that you can also help the environment by __________ on how much energy or water you use every day. Every little thing helps!

【1】A.set B.produced C.created D.found

【2】A.celebrate B.introduce C.suppose D.admire

【3】A.name B.subject C.saying D.sign

【4】A.protecting B.choosing C.watering D.planting

【5】A.what B.why C.whether D.how

【6】A.standard B.influence C.change D.effect

【7】A.humans B.animals C.factories D.plants

【8】A.useful B.bad C.special D.possible

【9】A.take out B.put out C.take in D.put in

【10】A.countless B.hopeless C.useless D.endless

【11】A.wild B.world C.forest D.space

【12】A.hardly B.never C.really D.almost

【13】A.spread B.pick C.plant D.try

【14】A.fastest B.best C.nearest D.hardest

【15】A.turning down B.pulling down C.cutting down D.speeding down