1. [由此及彼]根据已知单词的词义推断出其同根词的词义。
① accord n.一致；调和→disaccord n.
② obcordate a.倒心形的→cordate a.
2. [同义相连]常用词cardiac（心脏的，心脏病的）的词根cardi来自希腊名词kardia，而kardia与cordis在印欧语系中是同根词，意思都是heart（心）。试比较以下两列，把对等词用线连起来：
① cardiogram a.心力计
② cardiology b.心动图
③ cardiometer c.心病学
④ cardiotonic d.心脏炎
⑤ carditis e.强心剂
3. [寻根问底]指出下列单词的词根并领会其词义的由来。
① cardiograph n.心动描写器
② cardia n. [解] 贲门
③ cardiovascular a.心血管的
④ cardiorespiratory a.心肺的(提示：cardi=cord)
⑤ precordium n.心前区
precordial a.心前区的
⑥ concordat n.契约
4. [节外生枝] cord还有两个异体cor和cour。cor即拉丁名词cor的原形；cour来自法语。试分析下列几组单词的含义。
① core n.核心；果实的心
coreless a.无（果）心的
② courage n.勇气
courageous a.勇敢的；无畏的
③ encourage v.鼓励
encouragement n.鼓励
④ discourage v.使泄气
discouragement n.泄气；阻拦
19. cresc, cret, cre [L]=to grow生长
常用词crescent，increase，create和concrete，表面看来似乎关系不大，其实是同根生的。它们的词干部分cresc，cret和cre是一组同源异形根，都来自拉丁动词crescere，意为to grow（生长）。其中，cresc是不定式词干；cret是动名词词干；cre是cret在添加后缀时的变形。
crescent [cresc=to grow生长，变化；-ent n.=the state 表行为状态→“the growing state（of the moon）（月亮）变化的状态”→] n.① the visible part of the quarter moon which is growing larger or smaller月牙② any object like a crescent月牙形的东西/The national emblem of Turkey is a crescent.土耳其的国徽是个月牙。
increase [in-=into成；creas（cresc的重读式）=to grow生长；-e→] I v. grow into a larger amount;become greater or larger增长；增加；增大：The production increases with years. 生产逐年增长。→Ⅱn. growth增长：the rate of increase增长率
create [cre=to grow生长；-ate v.=to make使……→“to make to grow into shape使生长成形”→] v. make something exist 创造：to create more jobs创造更多的就业机会
▽creation [creat(e);-ion n.] n.创造；创作；（大写）创世
creator [creat(e);-or n.] n. 创造者；创始者；（大写）造物主 creature [creat(e);-ure n.] n.创造物；生物；动物
creative [creat(e);-ive a.] a.有创造力的；创造性的；创作的
concrete [con-=together一起；cret=to grow生长；-e→“to grow or stick together 长在一起或结成一块”→] I v. solidify or harden凝固；固结：The sands concreted into a mass. 沙土结成块。→Ⅱa. relating to a solidified thing; particular; real 固定有形的；具体的；实际的：a concrete problem 具体问题 III n. any mass of solidified particles, especially used in building 混凝土：reinforced concrete钢筋混凝土
▽concretion [concret(e) v.;-ion n.] n.凝固；凝固物
concretive [concret(e) v.;-ive a.] a.凝结性的
decrease [de-=downward向下；creas=to grow生成，变化；-e→“to grow downward 向下变化”→] I v. become less, or make less减少；使变少：Water comsumption decreased.耗水量降低了。→Ⅱn. reduction减少；减少量：A big decrease in sales caused the supermarket to close.销售量锐减使得超市关了门。
increment [in-=into成；cre=to grow生长；-ment n.=the result表行为结果→“the result of growing into a larger amount 数量增长的结果”→] n. the amount of increase 增加量：monthly increments 月增加额
▽incremental [increment;-al a.] a.增加的；增值的
increscent [in-=into成；cresc=to grow生长；-ent a.=-ing有……特征的→“growing into（the full moon）长成（满月）的”→] a. waxing of the moon（月亮）渐盈的：an increscent moon盈月
accretion [ac-（ad-）=to向；cret=to grow生长；-ion n.=the act or state 表动作或状态→“growing to向……生长”→] n.① continued growth生长；增大：the accretion of cancer肿瘤增大 ② growing of parts into each other合生，连生：accretion of two kinds of plants两种植物的合生现象
excrescence [ex-=out出；cresc=to grow生长；-ence n.=the result表行为结果→“growing or growth which is out of the normal state超出正常状态的生长物”→] n. ① abnormal outgrowth 赘生物，瘤：an excresence on the neck脖子上的瘤② superfluous part累赘，多余物：This tree is an excrescence in the painting.这棵树在画中是多余的。
▽excrescent [ex-;cresc;-ent a.] a.赘生的；多余的
