random: stresses chance and lack of definite aim, fixed goal, or regular procedure: a ~ sampling of public opinion.    （chance偶然是通用词，泛指由非理性不可控的力量决定determination by irrational, uncontrollable forces, 如leave things to chance听天由命Captain, a man in my position doesn't leave things to chance上校，我不会听天由命的）


haphazard: applies to what is done without regard for regularity or fitness or ultimate consequence: his selection of college courses was entirely ~.


chance: applies to what comes or happens to someone or is done or made without prearrangement, foreknowledge, or preparation: a ~ encounter; a ~ acquaintance.


casual: suggests a leaving things to chance and a working or acting without deliberation, intention, or purpose: a ~ tour of the sights.


desultory: implies a jumping or skipping from one thing to another without method or system and a consequently inconsistent performance and lack of continuity: a ~ discussion of current events.       consistent一致无矛盾。


hit-or-miss: applies to what is so haphazard as to lack all apparent plan, aim, system, care: a real ~ operation.


random随机: 强调偶然性，没有目标流程，haphazard随意: 不考虑规则恰当后果，chance偶然: 未预先安排准备知情，通用，casual随意: 没目标不考虑，放任事情发展，desultory散乱无条理: 从一处跳到另一处，缺乏系统方法不连贯，hit-or-miss全无计划: 完全随意无计划无方法不关心。


记忆方法: 1）首字母RHCCDH好蠢好蠢的人<==做事太随便


         2）随便的意思是出于偶然而非设计mean determined by accident rather than design.