名人教英文：即兴购买
an impulse buy
即兴购买
keiko: what's in that bag? i thought you went out for a walk, not to go shopping.
凯蔻﹕袋子里的是什么？我以为你只是出外散散步，不是去买东西。
erica: well i did, but when i passed the dress shop i saw this fantastic cocktail dress in the window and it was at half price. i had to have it.
埃丽卡﹕嗯，我本来是去散步的，但走过服装店，看见橱窗里这套鸡尾礼服，漂亮得很，而且半价，不能不买。
keiko: ok, let's see it. take it out of the bag and hold it against yourself.
凯蔻﹕好吧，看看是怎样的。拿出来，放在身前比比。
erica: there, what do you think?
埃丽卡﹕看，你认为怎样？
keiko: well it certainly suits you, but you've already got a very nice cocktail dress. you don't really need another one.
凯蔻﹕嗯，和你的确相配，但你已经有一套很漂亮的鸡尾礼服，不必再添一套。
erica: i know, but i couldn't stop myself. it was an impulse buy.
埃丽卡﹕我也知道，只是忍不住，即兴就买了。
cocktail dress，顾名思义，就是鸡尾酒会（cocktail party）上穿的礼服。这种礼服没有晚礼服（evening dress）那么隆重，裙子较短。
鸡尾酒当然是不同烈酒混合而成的饮料。为什么这种酒叫cocktail或「鸡尾」？按cocktail本来是指尾巴剪得短如鸡尾的马匹。猎马、驿马等，一般都有这样的「鸡尾」，都是cock-tailed horses。后来，杂种的赛马，也叫做cocktail，意思是其祖先之中，大概有「鸡尾马」。这cocktail和thoroughbred（纯种马）相对。而把cocktail的「杂种」意思引伸，以杜松子酒（gin）、威士忌（whiskey）等等加入香料混合而成的饮料，就是鸡尾酒，例如﹕we had a few cocktails at the christmas party（我们在圣诞聚会上喝了几杯鸡尾酒）。
impulse buy是「一时冲动买下的东西」。buy作名词，指「购买（的物品）」，一般用单数形式，例如﹕this watch was a good buy; i got it for only $100（这只手表买得很合算；我一百元就买下来了）。impulse直译是「冲动」。埃丽卡假如不说it was an impulse buy，则可以说﹕(1) i had an irresistable impulse to buy it（我有一股压不住的强烈欲望，要买下这套礼服）。(2) i bought it on (an) impulse（我一时兴起，买了下来）。至于「即兴买东西」这种行为，英文叫impulse buying / shopping，例如﹕shopkeepers do everything they can to encourage impulse buying（店东都千方百计，诱使顾客即兴买东西）。