Fill in the blanks with an appropriate verb form.

April 22 is ……………………….. (observing / observed) as Earth Day. The tradition ………………….. (begin / began / begun) in 1970 in the United States . U.S. senator Gaylord Nelson ……………………….. (felt / was feeling / had felt) that setting aside a day to recognize human impact on the environment ………………………… (is / was / has) necessary to raise awareness among the public.

 Nelson certainly ……………………… (achieves / achieved / has achieved) his goal. More than 20 million Americans ……………………. (participated / participate / participating) in the first Earth Day celebration, causing voter-hungry politicians to take notice. The overwhelming response ………………………….. (helps /helped / was helping) generate a new political focus on the environment. Today this focus …………………………. (has become / became / had become) increasingly global and more people than ever …………………………….. (is celebrating / are celebrating / have celebrated) Earth Day around the world.

Answers

April 22 is observed as Earth Day. The tradition began in 1970 in the United States . U.S. senator Gaylord Nelson felt that setting aside a day to recognize human impact on the environment was necessary to raise awareness among the public.

 Nelson certainly achieved his goal. More than 20 million Americans participated in this first Earth Day celebration, causing voter-hungry politicians to take notice. The overwhelming response helped generate a new political focus on the environment. Today this focus has become increasingly global and more people than ever are celebrating Earth Day around the world.