I often look back on my university days,which i regard as the happiest of my life为什么不能用WHEN,不是前面有my university days

I often look back on my university days,which i regard as the happiest of my life为什么不能用WHEN,不是前面有my university days look back on造句 look back on与look back into look back,bring back ,take back ,turn back的区别That was what I experienced on ____ back on my cildhood days.填哪个 英语翻译用 look back on look back on 是什么意思啊? look back on 与 look back to 有什么区别? look back at 与look back on区别 look back和 look back on用法一样吗? I can't look back when I look back on these days I will look and see your face!本人知识浅薄,急用 Dear past,stop tapping me on the shoulders.I don't want to look back Di empty in the car,I look back on everything.Heart pain Who can? sit,floor,often,on,and,out,look,beach,the,at,the,i连词成句 look back on the day and look back on和get back to的区别 问：look back,look on ,look down on ,look forward to I f____ the trees on both sides of the street moving back when i look out of the bus.