阅读文章的时候，我们时长会遇到很多不认识的单词，这些生词会影响我们的阅读理解甚至做题。那么遇到不认识的单词该怎么办？

相信很多同学是了解这个方法的，因为“词根词缀记忆单词”这个东东已经被人们鼓吹了很多年了，从老师还是个稚嫩少年的时候就已经听说过这个方法了（那个时候菊花还只是一种花）。实际上，词根词缀法是一个很好地在阅读中猜词的方法。同学们在备考阅读的时候需要掌握一些常见的词缀用以猜词意或判断方向性。我们来看下面的例子（第24题）：

题目：

　　23  Home medical aids

　　24  Regular amounts of exercise

　　25  Feelings of control over life

　　26  Feelings of loneliness

A  may cause heart disease.

B  can be helped by hormone treatment.

C  may cause rises in levels of stress   hormones.

D  have cost the United States government more   than $200 billion.

E  may help prevent mental decline.

F  may get stronger at night.

G  allow old people to be more independent.

H  can reduce stress in difficult situations.

原文：

　　Maintaining a level of daily physical activity may help mental functioning, says Carl Cotman, a neuroscientist at the University of California at Irvine. He found that rats that exercise on a treadmill have raised levels of brain-derived neurotrophic factor coursing through their brains. Cotman believes this hormone, which keeps neurons functioning, may prevent the brains of active humans from deteriorating.

分析：

利用题干中的信息(regular amounts of exercise)定位到原文(daily physical activity)，进而对该段文字进行阅读，发现最后的deteriorate不认识，但是以de-前缀开头，一般都是否定的方向，那么与第五个选项中的decline方向一致，可以确定E为正确答案。