1. [詞根辨異]現(xiàn)在又遇到一對異源同形根：cern的異體cret1=to separate；cresc的異體cret2=to grow。請指出下列單詞中詞根cret的含義：
excretion discrete secretary concretion
accretion discretion concretive secretive
2. [由此及彼]比較下邊兩列的構詞規(guī)律，填上相應的單詞：
increase 增加 decrease 減少
① increment 增加量 ________________減少量
② increscent ________________漸盈的漸虧的
3. [詞義判斷]選擇最恰當?shù)脑~義。
① recreate A.改造 B.消遣 C.再生
② re-create A.改造 B.消遣 C.再生
③ procreate A.生殖 B.催生 C.代生
4. [尋根問底]指出下列單詞的詞根并領會其詞義的由來。
① concrescence n.合生；增值
② decremeter n. [無]衰減計
③ decrescendo a. [音] 漸弱的
④ crescendo a. [音] 漸強的
⑤ accrete v.增大；合生
⑥ incrementalism n.漸進主義
20. cub, cumb [L]=to lie down躺
常用詞incumbent，succumb，concubine和incubate是一組同根詞。詞根cub來自拉丁動詞cubare，詞根cumb來自拉丁動詞cumbere；而cumbere和cubare實際上是同一個詞的異體，意思都相當于英語的to lie down（躺，臥）。
incumbent [in-=upon在……之上；cumb=to lie down躺；-ent a.=-ing……的→“lying upon somebody躺在或賦予某人身上的”→] I a. lying or resting on（somebody）as an obligation作為責任的：It is incumbent on you to warn them.你有責任告誡他們。→Ⅱn. person on whom an obligation lies;one who holds public office負有責任者；任公職者：the struggle between the incumbents and the candidates現(xiàn)任者與候選人之間的斗爭
▽incumbency [in-;cumb;-ency n.] n.責任；任職；職權
succumb [suc-（sub-）=under在……之下；cumb=to lie down躺倒→“to lie down under pressure, illness etc.在壓力、疾病等之下躺倒”→] v.① give way;yield讓步，屈服：We will not succumb to difficulties.我們決不向困難低頭。② die死：He succumbed to cancer.他死于癌癥。
concubine [con-=together共同；cub=to lie down臥；-ine n.=female女人→“woman who lies down together with a man與某男人同臥共宿的女人”→] n. woman who inhabits with a man without being married姘婦，情婦
▽concubinage [concubin(e);-age n.] n.情婦身份；非法同居
incubate [in-=on在……上；cub=to lie臥；-ate v.=to cause使……→“to cause (a hen, etc.) to lie on eggs 使（母雞等）臥在卵上”→] v.①sit on eggs in order to hatch them孵卵，孵化：Even a good hen can't incubate a wooden egg.母雞再好也孵不了木頭蛋。② give form to;develop把……醞釀成熟；使發(fā)展：to incubate a plan 醞釀一個計劃
▽incubation [incubat(e);-ion n.] n.孵化；醞釀
incubator [incubat(e);-or n.] n.孵化器
incubative [incubat(e);-ive a.] a.孵卵的；潛伏期的
incubus [in-=upon在……之上；cub=to lie down臥；-us n.=thing物→“thing inclined to lie down upon a person喜歡臥在人的身上的東西”→] n. evil spirit supposed to lie down upon sleeping persons;nightmare壓在睡眠者身上的惡魔；夢魔：The debt is like an incubus on me.這筆債務使我夢寐不安。
cubicle [cub=to lie躺；-icle n.=small thing 小東西→“small room for lying down供躺下歇息的小房間”→] n.① small bedroom小臥室② any small room小室
▽cubicular [cub;-icular a.] a.寢室的
recumbent [re-=backward向后；cumb=to lie躺；-ent a.=-ing……的→] a. lying backward;reclining躺著的；斜臥的：recumbent statue雕塑的臥像
▽recumbency [recumben(t);-cy n.] n.斜臥；依靠
procumbent [pro-=forward向前；cumb=to lie躺；-ent a.=-ing……的→“lying forward向前臥著的”→] a. leaning forward;prostrate;prone前俯的；平臥的；爬在地下的：The man fell procumbent on the ground.那個人摔了個嘴啃泥。
