single: implies being unaccompanied or unsupported by, or not combined or united with any other: a ~ example will suffice.  


sole: applies to the only one that exists, acts, has power or relevance, or should be considered: my ~ reason for moving there.


unique: applies to the only one of its kind or character in existence: the medal is ~, for no duplicates were made.


separate: stresses discreteness, or disconnectedness, or unconnectedness from every other one: a country with a ~ set of problems. (discrete不同： 是看似接近连续实际分离不同的不同，如: two discrete problems are confused here把两个不同问题搞混了)


solitary: implies being BOTH single and isolated: television was her ~ link to the outside world.


particular: implies singular or numerical distinctness from other instances, examples, or members of a class: a very ~ kind of wine.  (singular有3个意思: 1非常突出, 2奇怪让人困惑,3单数，如 smile of singular sweetness非常甜美的微笑，singular feeling of impending disaster奇怪地感觉有灾难降临)  (numerical数字上的，没有译出)


single单一: 表示没有其它陪伴支持结合联合，sole唯一:  表示只有一个存在或行动有权相关应当考虑，unique独一无二: 只存在一个,(不像sole除可能表示只存在一个外，还可能表示存在多个但只考虑一个或只让一个起作用，unique则限定是只存在一个），separate单独各自:  强调分离不同(discrete)，与其他断开连接(disconnected)或从未连接(unconnected)，solitary也是唯一: 除了表示唯一还表示被隔绝(如solitary confinement单独关押，he is a solitary man他惯于独处)，particular独特: 和其他样本成员等非常不同。


记忆方法: 1）首字母SSSS UP想成四海升平<==唯一使命


         2）唯一的意思是一个而不是两个或更多mean one as distinguished from two or more or all others.