(2) 上下文线索

　　利用上下文线索猜测词义的方法很多，但其核心是寻找与该生僻词相关的上下文意义线索，这些线索主要可归纳为以下几种：

　　①同义定义为了便于读者理解作者本义，作者有时会对文中的生僻词或专业性较强的词直接给出定义。在下定义时，作者常使用一些信号词， 如：is/are(called)，means，can be defined as，refer to，is/are known as，signify等，例：

　　Food fallacies refer to beliefs about food that are not true.

　　或标点符号，如——，()等，例：

　　Multiplexing ——transmitting independent signals at the same time in the same channel——increases the efficiency of radio channels.

　　有时，作者用同位语形式或连词or给出定义，例：

　　Nerve cells evidently first appeared in coelenterates, “hollow瞘utted” organisms like hydra and the sea anemone.

　　Intelligent behavior remained impossible until the appearance of relatively big，complex types of brain——the types we find among the vertebrates，or backboned animals.

　　②近义复述同一短文中上下毗邻的句子通常有互释作用，我们可以从上下文的复述中获取与某一单词相关的信息来猜度词义。例：

　　Mr. and Mrs. Firth had a long courtship. They dated for nine years before they got married.

　　Although he often had the opportunity，Mr. Tritt never stole money from a customer. This would have endangered his position at the bank，and he did not want to jeopardize his future.

　　③反义对照在表示对照的上下文中，常包含有意义相反的词语或概念，这些意义相反的概念可以互为线索，帮助我们猜度词义。常有以下一些信号 词：although，but，however，though，whereas，while，yet，on the contrary，on the other hand等。

　　例：Chimpanzees(猩猩) in the wild use simple objects as tools，but in laboratory situations they can use more sophisticated items.

　　Most dentists-offices are drab places，while Emilio’s new office is a bright，cheerful place.

　　④搭配集合利用词与词的搭配或该词所出现的语境，我们也能推知词义的大概轮廓。例：

　　People gathered to look. Three fine streams of hot water sprouted from holes in the jacket(套，壳) of the radiator.

　　A man is watering his lawn just as an attractive，well dressed girl walked by. As he ogles her，he accidentally turns the hose on his ugly，dowdy wife.

　　⑤比较举例上下文中的比较和举例，能揭示比较物或列举物之间的共性，我们可根据这些共性来推知有关词语的意思。例：

　　The consequences of epochal events such as wars and great scientific discoveries are not confined to a small geographical area.

　　Doctors believe that smoking cigarettes is detrimental to your health. They also regard drinking as harmful.

　　⑥因果时间因与果、时间的先与后都是事物发展变化过程中的必然关系，在利用上下文推测词义时，这些关系也至关重要。例：

　　Robert is considered peremptory administrator because he makes decisions without seeking the opinions of others.

　　When Mark was in pedantic mood，he assumed the manner of a famous professor and gave long lectures on boring, insignificant topics.