obscure: implies a hiding or veiling of meaning through some inadequacy of expression or withholding of full knowledge: the poem is ~ to those unlearned in classics.   （hide隐藏，veil掩藏既可有意也可无意，veil面纱朦胧）   （withhold保留不公布，常表示合理: withheld information from authorities当局保留信息，本例to withhold full knowledge保留不说出全部）


dark: implies an imperfect or clouded revelation often with ominous, mysterious, or sinister overtones: muttered ~ hints of revenge.   （overtone暗示意味=suggestion, connotation）


vague: implies a lack of clear definition or formulation because of inadequate conception or consideration: made ~ promises of reimbursement.   报销  (conception构思: 是想象构造concept概念的过程，常指特定独特的概念)


enigmatic: stresses a puzzling, mystifying quality: left behind ~ works on alchemy.    （puzzle使人难懂难解决，是基本词只能死记） （又如the enigmatic smile of Mona Liza蒙娜丽莎的神秘微笑，形容她微笑几乎千篇一律用enigmatic）


cryptic: implies a purposely concealed meaning and often an intent to perplex or challenge: a ~ message only a spy can decode.


ambiguous: applies to a difficulty of understanding arising from the use, usually inadvertent, of a word or words of multiple meanings: an ~ directive that can be taken either way.   （还可形容颜色难判断，如瞳孔是黑色褐色？海水是蓝色绿色？可以说the color of the eye/sea is ambiguous难判断）   （inadvertent没有意识到犯错，疏忽，如an inadvertent error一个疏忽错误）


equivocal: applies to the deliberate use of language open to differing interpretations with the intention of deceiving or evading: the prisoner would give only ~ answers.


obscure晦涩: 表示意思隐蔽，因为表达不充分或保留不说，dark黑暗: 形容表达得不清楚，有不祥神秘邪恶的意味 ，vague模糊: 表示没有清晰的定义形式，因为缺乏构思考虑，enigmatic神秘: 表示神秘难懂，cryptic加密: 故意隐藏含义，迷惑挑战别人，ambiguous有歧义难判断: 使用的语言可以有多种解释， equivocal模棱两可: 指故意使用有多种解释的语言，以欺骗或逃避


记忆方法: 1) 首字母DOVE ACE最好的鸽子<==意思难懂     （ace扑克里的A,表示最好，如an ace film最好的电影，短语holds all the aces占尽优势China held all the aces in the war中国在战争中占尽优势，an ace in the hole王牌绝招technology is our ace in the hole科技是我们的王牌）  

         2) 难懂的意思是难以清晰理解mean not clearly understandable.首字母DOVE ACE最好的鸽子<==意思难懂