【问】 (1) A table made of steel costs more than____made of wood.
 A. that B. which is
 C. it is D. one (EPT)
 (2) Specific gravity is defined as the ratio of the density of a substance to____of water.
 A. one B. that
 C. the ratio D. those
 我不明白，为什么试题(1)只能选D(one)，而不能选A(that)，也不明白为什么试题(2)只能选B(that)，而不能选A(one)。
 【答】 这是中国学生和教师经常提出的一个问题。一般而论，that与one在替代前面的名词时，大致有如下几个区别：
 A ：that替代带定冠词的名词，如试题(2)，而one替代带不定冠词的名词，也就是说，that替代有定的名词，one替代无定的名词，如试题(1)：
 1. The potato crop in 1846 was inferior to that of 1815. (that 替代the potato crop)
 1846年的土豆收成不如1815年。
 2. The Korean climate is more pleasant than that of Japan.
 朝鲜的气候比日本好。
 3. I am looking for a flat. I’d like one with a garden. (one 替代a flat)
 我正在寻购一套单元房。我想买一套带花园的。
 4. Imagine the effect on a reasonably advanced technological society，one that still does notpossess the bomb，of making it aware of the possibility，of supplying sufficient details toenable the thing to be constructed. (New Concept English，Book 4，L. 57)
 如果让一个科学技术相当先进但是尚未拥有原子弹的国家知道制造原子弹的可能性，并向它提供制造原子弹的充分的细节，请设想一下这会产生什么样的作用吧!
 当one的先行词为名词复数时，则该名词可以带定冠词：
 The clean towels are in the drawer—if you need one. (one实际上替代的是a clean towel)
 B：that既可用来替代可数名词，亦可用来替代不可数名词，而one则不能替代不可数名词：
 1. The victim's own blood was of a different blood group from that found on the floor.(CGEL)
 受害者本人的血型与在地板上发现的血的血型不同。
 2. An internationally famous ballerina，Maria Tallchief demonstrated that the quality ofballet in the United States could equal that of the ballet in Europe. (TOEFL，85. 11)
 一位国际著名的芭蕾舞女演员玛丽娅·托尔契芙表明，美国芭蕾舞的水准与欧洲芭蕾舞的不相上下。
 3. Anderson has never been out of the United States，yet his accent is very similar to thatof an Englishman. (TOEFL，73. 1)
 安德逊从未离开过美国，不过他的口音却非常象英国人(的口音)。
 4. Social life in a village cannot compare with that of a large city.(LDPV)
 乡村的社交生活是不能与大城市的社交生活相比的。
 C.that不能替代表人的名词，而one却可以：
 1. A hateful person is one that arouses feelings of hatred in you. (Neal)
 可恨的人就是让你内心里产生厌恶之感的人。
 2. The girl I saw was older than the one you were dancing with.
 我看到的那个女孩比和你跳舞的那个女孩年龄大。
 D.that只能带后置修饰语，而one既可带后置修饰语，也可带前置修饰语：
 1. My seat was next to that of the mayor. (Eckersley)
 我的座位紧挨着市长的座位。
 2. The question was a complicated one. (Dreiser)
 这个问题是一个复杂的问题。
 3. The first question is one which Jackson has anticipated. (Cronin)
 第一个问题是杰克逊所预料到的一个问题。
 E.用以替代前面出现的名词的that，其定语从句不能使用关系代词who，也不能使用that或零关系代词，而one却可以：
 The problem confronting us today is not dissimilar from that which the nation confronted inthe 1930s. (CGEL)
 今天所面临的问题和国家三十年代所面临的问题并不是不一样的。
 请做下面的英语试题：
 A good writer is____who can express the commonplace in an uncommon way.
 A. that B. he C. one D. this