第一节 完形填空（共10小题；每小题2分，满分20分）
阅读下面短文，掌握其大意，然后从21~30各题所给的A、B、C和D项中，选出最佳选项，并在答题卡上将该项涂黑。
The requirements for high school graduation have just changed in my community. As a result, all students must 21 sixty hours of service learning. Or they will not receive a diploma（文凭）. Service learning is academic learning that also helps the community. 22 of service learning include cleaning up a polluted river, working in a soup kitchen, or tutoring a student. During a service experience, students must keep a journal and then write a 23 about what they have learned.
