1.rating n.等級：定額(a classification according to grade)
例：Ratings of productivity correlated highly with ratings of both accuracy and attendance. //Managers responded that productivity was the critical factor in assigning ratings.

2.ratio n．比例(proportion)

詞根記憶：rat(計算)+io——和計算有關(guān)的——比例
例：Statistics show that the ratio of women's earnings with that of men have been roughly static since 1960.

3.ration n．定量配給（食物等）(fixed quantity, esp. an official allowance of food, etc. in times of shortage)
詞根記憶：rat(計算)+ion——計算著給——配給
例：a rationing mechanism配給機(jī)制

4.rational a．合理的，理性的(having reason or understanding);n．有理數(shù)(an integer or a fraction)
詞根記憶：ration(理性，定量)+al——理性的，合理的
例：The majority of successful senior managers do not closely follow the classical rational model of first clarifying goals.
派生詞：rationally( ad.理性地)
同根詞：rationalistic(a．理性主義的；純理論的)

5.rationale n．根本性的依據(jù)（an underlying reason, basis）
詞根記憶：rat(計算)+ion+ale——通過精密計算——根本性的依據(jù)
例：My professor disagreed with the rationale of my argument.

6.reactor n．起反應(yīng)的人(one that reacts)；【原】反應(yīng)堆(a device for the controlled release of nuclear energy)
詞根記憶：react(反應(yīng))+or——發(fā)生反應(yīng)的東西——反應(yīng)堆
例：nuclear reactor核反應(yīng)堆

7.readily ad.樂意地(willingly)；容易地(easily)
例：l Women accepted the more unattractive new industrial tasks more readily than did men.//Such foods are more readily available in China than in the U.S

8.realm n．領(lǐng)域(domain)；國度(kingdom)
聯(lián)想記憶：real(真正的)+m——真正的好東西（如音樂，藝術(shù)）無國界——領(lǐng)域；國度
例：the realm of science科學(xué)領(lǐng)域

9.rear v.撫養(yǎng)(to bring up)；a．后面的(being at the back)
例：The identical twins were reared apart from each other.//rear wheel后輪