costly: implies a high price and may suggest sumptuousness, luxury, or rarity: the ~iest food graced her table.


expensive: may furthre imply a price beyond the thing's value or the buyer's means: the resort's shops seemed rather ~.


dear: implies a relatively high or exorbitant price or excessive cost usually due to factors other than the thing's intrinsic value: coffee was ~ during the war.


valuable: may suggest worth measured in usefulness or  enjoyableness as well as in market value: iron is a ~ commodity.


precious: applies to what is of great or even incalculable value because scarce or irreplacable: our ~ natural resources.


invaluable: implies such great worth as to make valuation all but impossible: a good education is ~.


priceless: used like invaluable in a hyperbolic sense, adds a note of even greater intensiveness: a bon mot that was ~.     (hyperbolic夸张)            bon mot妙语;诙谐的话=a clever, funny, or witty remark


costly: 价格高，暗示奢侈或稀少，expensive: 超出价值或承受能力，dear: 由于非本身价值的其他因素，valuable: 有用有市场价值，precious: 稀少、无法替代，invaluable: 价值大到无法估量，priceless: 和invaluable相同，语气更强


记忆方法: 1) CEDVPIP首字母联想，重组为VIP DE PC重要人物的电脑<==价格非常昂贵   前三个词表示价格(price)高，后四个词表示价值(worth or value)高有用或稀少

               2) 昂贵的意思是价值或价格高mean having a high value or valuation, especially in terms of money.   CEDVPIP首字母联想，重组为VIP DE PC重要人物的电脑<==价格非常昂贵