阅读下列短文，根据短文内容填空，在未给提示词的空白处仅填写1个适当的单词，在给出提示词的空白处用括号内所给词的正确形式填空。

Earth Day, ________ (mark)on 22 April, is an annual event aiming to raise public awareness about environmental protection. First celebrated ________ 1970, the Day now includes events in more than 190 countries and regions (地区). No matter what you like to do, there is a way to get involved in various ________ (activity) on Earth Day. You can plant a tree, make a meal with locally grown vegetables, or save power-the possibilities are endless.