In many countries of western Europe, the numbers of student in higher education doubled within five - year periods during the 1960s and doubled again in seven eight or 10 years by the middle of 1970s.
断句：
① In many countries of western Europe,
② the numbers of student in higher education doubled within five - year periods during the 1960s
③ and doubled again in seven eight or 10 years by the middle of 1970s.
各部分结构：
① 地点状语：In many countries of western Europe,
②主语( the numbers of student)+定语( in higher education)+谓语( doubled )+状语(within five - year periods during the 1960s)
③ and +并列谓语(doubled again )+状语(in seven, eight or 10 years by the middle of 1970s. )
参考译文：在西欧很多国家，二十世纪六十年代时，接受高等教育的学生数量五年内翻了一倍，至七十年代中期，该数量在七、八年或者十年间又翻了一倍。