阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。
Earth Day began in 1970．Every year on 22 April people are(1)_________ (call) on to take better care of our planet. On this day people help clean up rivers, lakes, parks and (2)_________(beach). We can keep the earth clean by (3)_________(follow) rules like “Reduce, Reuse, Recycle”. “Reduce” means to use (4)_________ (little). We can use less energy, paper, water etc. Or we can ride (5)_________ bike or walk to use less gasoline. Turn off unnecessary lights to (6)_________(save) electricity. “Reuse” means to use again. We can reuse many things, such(7)________ jars, bags and boxes. Make old jeans into a cool bag.
Use old newspapers for art projects. Give old clothes(8)________ are still in good condition to other people. “Recycle” (9)._________ (mean) to make something new from something old. We should recycle bottles and paper. Recycle garbage to reduce (10)_________(pollute).
