Language points
1.It is nice to look back on my schoolday in the countryside.  look back on (upon) / look back to   回顾；回
我的爷爷奶奶总
My grandparents often look back on their bitter life in the old society.
2nd-Detailed points:
知识链接：look for look up look intolook forward to look down look down on
寻找；向上看;尊敬;仰视； （在词典、参考