阅读下面短文,在空白处填人1个适当的单词或括号内单词的正确形式。
Chuck Wall teaches management and human relations at Bakersfield College. One day, he told his students that their homework was to perform a simple and random act of kindness. Not 10 (understand) the homework, the students didn't know what to do. Chuck didn't answer their questions. 11 ,he encouraged his students to work it out by themselves.
One week later, the students entered the classroom and began sharing their stories 12 (excited). One student reported helping a poor dog 13 (abandon) by its owner. Another student told others about giving blankets away to the homeless. Gradually, more and more students developed the habit of doing such kind acts, from 14 they benefited a lot.
Since then, similar kind acts 15 (perform) in schools around the world. Many schools organize a Random Acts of Kindness Week 16 (celebrate) World Kindness Day. Some schools use each day of the Random Acts of Kindness Week to perform a 17 (differ) kind act, such 18 making a new friend, helping someone, doing community service or raising money for a charity. In this way, students learn to consider other people and think about how small actions can make the world a 19 (good) place.