1 .they often have four classes in the morning
-In the afternoon, they have about three more classes
2. the recess is twenty-minute
3. because it is time for a break
4. During the recess ,the yard and classroom"s are very noisy
5. some play games like blindman"s bluff or catch , some girl skip rope ,some boys play marbles or swap baseball cards
6. these activities only stop when the bell rings