replace: implies a filling of a place once occupied by something lost, destroyed, or no longer usable or adequate: the broken window will have to be ~d.


displace: implies an ousting or dislodging or crowding out, often preceding a replacement: thousands had been ~d by the floods.  （dislodge从固定位置上强行去除移走means to remove something from where it was fixed or held，如rainfall had dislodged debris from the slopes of the volcano雨水冲走了火山坡面上的岩屑，如he dislodged the rock with a shovel他用铲子把石头铲开， 如they tried to dislodge the leader希望将领导人赶走）  解释中的3个关键词都有字母o


supplant: implies either a dispossessing or usurping of another's place, possessions, or privileges or an uprooting of something and its replacement with something else: discovered that he had been ~ed in her affections by another.  uproot根除赶走    usurp篡夺，指非法侵占他人财物财产


supersede: implies the replacing of a person or thing that has become superannuated, obsolete, or otherwise inferior: the new edition ~s all previous ones.   注意是supersede，不要错写成cede，词根sede表示坐sit，好像新的事物'坐'到了旧事物上，而cede表示前进


replace替换: 指填补位置，换掉丢失毁坏或不满意的，displace赶走: 指赶走去除挤出，发生在替换之前，supplant取代: 指篡夺或赶走进而取代，supersede取代: 指替换掉老旧过时劣质的


记忆方法:  1）首字母RDSS想成人生的事<==替代  人事有代谢，往来成古今    "代"表示"新老交替迁移"，本义是"相邻两辈人血统的迁移"，字从人从弋，"弋"为戈的省略形式，是古代巡逻迁移时常用的武器，人与弋合起来表示"人际的迁移"或"辈分的迁移"，即新老交替迁移，如代替代办代销代序代数代表；引申为"辈分"、"时期"，如老一代下一代，如时代古代现代年代汉代朝代当代    "替"表示"代替"，最早是"两个人并排站立"，本义是"废弃"，如久替表示长期废弃，如朝代兴替表示衰亡，引申义是"代替"，如替身替罪替工替补替人办事

          2）替代的意思是移除某物mean to put someone or something out of a usual or proper place or into the place of another.