词根词缀法是考研英语背单词的好方法，科学合理，一旦掌握了，猜词能力也会大大提升。新东方网考研频道建议大家记忆词根词缀可以按分类来看，下面是10类表示反义否定的前缀，大家先看看记下来。

　　1、a-/an- (not，without否定)

　　apo1itical a. 不关心政治的

　　e.g. Henry used to be totally apolitical, but I think he is now politically more aware

　　基辛格过去完全不问政治, 但是,我认为现在他政治上比较敏锐了.

　　anonymous a. 匿名的，无名的，不知名的

　　e.g. She's got too much dignity to descend to writing anonymous letters.

　　她是个自尊心很强的人，绝不会自贬身份去写匿名信。

　　2、a-/ab-/abs- (在"t""v"之前)( avoid避免)

　　abstain v.弃权，戒

　　e.g. They say it would be political suicide for the party to abstain.

　　他们说这个政党弃权无异于自毁政治前程。

　　abstract v. n. 摘要

　　e.g. His painting went through both representational and abstract periods.

　　他的绘画经历了具象风格和抽象风格两个阶段。

　　3、ant- (against /opposite"反抗""反""抗")

　　anti-government反政府的

　　e.g. Mr Cramer said the violence by anti-government protestors was reprehensible.

　　克拉默先生说反政府示威者的暴力活动应该受到谴责。

　　antisocial反社会的

　　e.g. Toddlers are notoriously antisocial when it comes to sharing toys.

　　众所周知，刚学会走路的孩子不愿和别人分享玩具。

　　4、counter-/contra- (against，opposite反，对应)

　　contrast对比，对照;

　　e.g. The boy's room is a complete contrast to the guest room.

　　这个男孩的房间和客房截然不同。

　　counteract抵抗;

　　e.g. My husband has to take several pills to counteract high blood pressure.

　　我丈夫不得不吃几片药来降压。

　　5、de- away，down，negative离开，分，否定，使低下

　　decompose v. 分解, 腐烂

　　e.g. Most animals decompose very quickly after death.

　　大多数动物死后很快腐烂.

　　degenerate v. 堕落

　　e.g. Will too much freedom make them degenerate?

　　太多的自由会令他们堕落吗 ?

　　6、dis-(加在名、形、动词前)表示"不，不再"

　　disadvantage n. 不利，不利条件;

　　e.g. Depression is the third thing that works to my patients' disadvantage.

　　抑郁是威胁我的病人健康的第三大杀手。

　　disappear. v. 消失

　　e.g. He saw something dark disappear behind the curtain of leaves.

　　他看到一个黑漆漆的东西从浓密的树叶后消失了。

　　disconnect. v. 分离

　　e.g. You should disconnect the wireless set before you make adjustments inside it.

　　你应先拔掉无线电插头,再做内部调整。

　　7、di-,dif-, dis-： away，negative否定，分开，不

　　distrust. v. 不信任, 怀疑

　　e.g. What he saw there left him with a profound distrust of all political authority.

　　他在那儿的所见让他对一切政治当局产生了一种深深的不信任感。

　　disassemble v. 拆开

　　e.g. We had to completely disassemble the engine to find the problem.

　　我们只好把发动机全部拆开以寻找故障原因。

　　differentiate v. 区分

　　e.g. A child may not differentiate between his imagination and the real world.

　　儿童可能无法将自己的幻想与真实世界区分开来。

　　8、il-：(加在以"l"开头的词前)表示"不"

　　illiterate n. 文盲;

　　e.g. Many senior managers are technologically illiterate.

　　许多高级经理都对技术知之甚少。

　　illegitimate a. 非法的

　　e.g. The election was dismissed as illegitimate by the opposition.

　　反对党以不合法为由拒绝接受选举结果。

　　9、im-，in-(加在字母m，b，p之前)not，in，into否定，加强或引申意义

　　impracticable行不通的

　　e.g. Such measures would be highly impracticable and almost impossible to apply.

　　这样的措施非常不切实际,几乎不可能付诸实施。

　　invisible不可见的;

　　e.g. Parents fear they might overstep these invisible boundaries...

　　父母担心他们可能会逾越这些无形的界限。

　　irrational不合理的;

　　e.g. His behavior was becoming increasingly irrational.

　　他的行为变得越来越不理智了。

　　10、mal- bad，badly：恶，不良

　　maltreat虐待;

　　e.g. He said that he was not tortured or maltreated during his detention...

　　他说自己在押期间并未遭受拷问和虐待。

　　malnutrition营养不良

　　e.g. Infections are more likely in those suffering from malnutrition.

　　营养不良的人更有可能被传染。