He has to go to the classes at certain times of the month.他必须在每个月的特定时间去上课。There is a ten-minute break between the classes.课间有十分钟休息时间。We have significantly increased the number of people in education but the size of the classes hasn't changed proportionately.受教育的人数显著增加了，可是班级人数并未相应增加。