准关系词as,than和but准关系词as,than和but

准关系词as,than和but

关系词通常是用来引导定语从句的,但as, than和but这三个词却与which, who, that, where, when和why等典型的关系词不同｡三者本身具有常见的字面意义,前面有名词作先行词,但后面的定语从句却不像典型的定语从句｡这些既像连接词又像关系词的词,我们就姑且称它们为准关系词｡下面对其逐个作一分析:

　　一､ as作为准关系代词,出现在the same ... as, such ... as, 和as ... as等结构中｡这时, as前面通常要有名词; as后面的从句意义上不像是通常的定语从句; as需要在从句中充当一定的句子成分｡

　　1. the same ... as

　　(1) as在从句中作主语｡例如:

　　She is the same person as came here last Sunday. 她就是上星期天来这儿的那个人｡

　　(2) as在从句中作宾语｡例如:

　　This is the same watch as I lost while I was doing the sightseeing in Shanghai three months ago. 这块表跟我三个月前在上海观光时丢失的那块一样｡

　　(3) as在从句中作be动词的表语｡例如:

　　China is not the same country as it used to be. 中国已今非昔比｡

　　(4) as在从句中作行为方式状语｡例如:

　　You should learn to do housework in the same way as your mother does it. 你应该学会像你母亲那样做家务活｡

　　2. such ... as

　　(1) as在从句中作主语｡例如:

　　Let children read such books as tend to make them better and brighter. 让孩子看那些容易让他们变得更好更聪明的书｡

　　(2) as在从句中作宾语｡例如:

　　This is not such an interesting book as you just talked about. 这不是你们刚才谈到的那种有趣的书｡

　　(3) as在从句中作be动词的表语｡例如: Such a bad man as he is will be punished. 像他这样的坏人一定会受到惩罚｡

　　3. as ... as

　　(1) 第二个as在从句中作主语｡例如:

　　He has as much money as is required. 他要多少钱就有多少钱｡

　　(2) 第二个as在从句中作宾语｡例如:

　　I have as many friends as you (do). 我的朋友和你的朋友一样多｡

　　(3) 第二个as在从句中作be动词的表语｡例如:

　　He is as advanced a worker as Ms Smith (is). 他是一位和史密斯先生一样的先进工人｡

　　有时as可单独用来引导非限制性定语从句｡这种定语可位于主句之前｡例如:

　　As is known to all, Taiwan is one of the Chinese provinces. 众所周知,台湾是中国的一个省｡

　　二､ than作为准关系词时,出现在more ... than, less ... than, fewer ... than等结构中｡这时, than前面要有名词; than本身有比较意义,而且需要在从句中充当一定的句子成分｡

　　1. than在从句中作主语｡例如:

　　Take it casy; I have more money than is needed. 放心,我的钱比所需要的还多｡

　　2. than在从句中作宾语｡例如:

　　I have more/fewer books than you (do). 我的书比你的多/少｡

　　3. than在从句中作be动词的表语｡例如:

　　He is a better boy than you (are). 他是一个比你更好的男孩｡

　　三､ but作为准关系词,本身含有否定意义,它前面的主句还有另一个否定意义｡这时but在意义上相当于“who ... not ...”或“which/that ... not ...”｡

　　1. 定语从句中有be动词,并将其改为含but的复合句时, be动词后面不能再有not｡ 例如:

　　There is no one who is not conccrned about his future. (= There is no one but is concerned about his future.) 没有人不关心自己的未来｡

2. 定语从句中有can, will, shall, must, may, should, ought to等助动词或情态动词,在将其改为含but的复合句时,这些助动词或情态动词后面不能再有not｡ 例如:

　　There is nothing that she can’t do. (= There is nothing but she can do.) 没有她做不到的事｡

　　3. 定语从句中有助动词do, does, did, 在将其改为含but的复合句时,应去掉do, does, did, 还原其后动词的时态及人称变化｡例如:

　　There is no one who doesn’t wish to make great achievements. (= There is no one but wishes to make great achievements.) 谁都希望自己将来能有所成就｡

　　There was not a man that did not take pity on the woman whose husband had just died. (= There was not a man but took pity on the woman whose hushand had just died.) 大家都很同情那位刚刚丧夫的妇女｡