free period

例句：

1. 1.During the free period, she enjoys reading books.
   在空闲时间里，她喜欢阅读书籍。
2. 2.The teacher gave us a free period to review our homework.
   老师给了我们一个自由时间来复习作业。
3. 3. After class, there is usually a free period for students to do extra practice.
   课后通常有一个自由时间供学生做额外的练习。