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一. 构词法
中国的汉字会有偏旁部首，而英语词汇也是如此。词汇的构成有一定规律可循，通常有如下两种：
1. 合成法：将两个单词合成构成一个新词。
out + break = outbreak 爆发
down + hill = downhill 下坡的
over + throw = overthrow 推翻
hot + foot = hotfoot 匆忙地
before + hand = beforehand 事先
2. 派生法：在词根前后加上前缀或后缀，构成一个与原单词意义相近或截然相反的新词。
前缀：
value (名词，价值) + de-(下，向下) → devalue (动词，降低…的价值)
little (形容词，小的) + be- (使……成为)→ belittle (动词，轻视)
后缀：
inflame (动词，点火) + -ability (能……) → inflammability (名词，易燃性)
conceive (动词，设想)+ -able(可……的) → conceivable (形容词，可想象的)
例题：This unprecedented development of a finite groundwater resource with an almost negligible natural recharge rate—that is, virtually no natural water source to replenish the water supply—has caused water tables in the region to fall drastically.
Q: The word “unprecedented” in the passage is closest in meaning to
A: difficult to control
B: without any restriction
C: unlike anything in the past
D: rapidly expanding
解析：un表示not没有，pre表示before之前，precede是在……之前的意思，所以选择C正确。
二. 语境法
根据上下文语境内容来推断出某个词汇的含义，就是语境法。通常托福阅读中考查到以下两种语境：
1. 并列语境：所考查的词汇跟前后形成一个同义的关系。
例题：Given a year of favorable precipitation, such plants will develop vigorously and produce large numbers of flowers and fruit.
Q: In saying that ephemerals will develop “vigorously" when there is favorable precipitation, the author means that their development will be
A: sudden
B: early
C: gradual
D: strong and healthy
解析：可以利用句子的并列关系来推测，develop vigorously和生产大量的花和果实并列，那么很明显，D选项最合适。
2. 转折语境：所考查的词汇跟前后形成一个相反的关系。
For example, a pond in hilly country that maintains a steady water level all through a dry summer in spite of having no streams flowing into it must obviously be seepage dominated. Conversely, a pond with a stream flowing in one end and out the other, which dries up when the stream dries up, is clearly surface water dominated.
Q: The word Conversely meaning to
A: on the other hand
B: in the same way
C: in other words
D: on average
解析：原句说有河水流入流出的是surface water dominated，前一句说一个没有地表水流入的pond是seepage dominated，那么后文当然与之相对，所以正确答案是A。
三. 归纳法
“狂背单词，疏于整理”是一大误区。积累单词的同时，要进行整理归纳，以下有两种推崇的方法：
1. 意群法：将意思相近的单词放在一起进行记忆。
吝啬：stingy, penurious, niggardly, miserly, parsimonious, petty
贫穷：indigent, impoverished, destitute, penniless, impecunious, poverty
2. 类比法：将形式相近的单词放在一起进行记忆。
infect v.感染，传染
affect v.影响;感染;感动;假装
inflect v.弯曲;改变;使屈曲
effect n.影响;效果;作用
词汇 语境 单词