Choose the words or expressions and complete the passage.

    People enjoy1with kites. There are kite festivals and competitions (比赛) in China, Japan and many other countries. But kites are not just for playing. They are used in many other ways, too. Flying kites has been popular in China for more than2. Scientists are also 3in kites. They have4them for studying weather, and testing (测试) new machines. People like flying kites,5flying kites is both an art and a science. It is fun, too.