词根：tend, tens, tent = to stretch（伸）
tend,tens,tent这三个为同源异形根，tend来源于拉丁动词tendere, 意为to stretch（伸开，伸长，延伸）；tens和tent都是这个拉丁动词的动名词词干（tendere有两个动名词形式:tensum和tentum），主要用来构成相应的名词和形容词。
同源词：
1. contend （con<com(=together) + tend(=stretch)相互拉扯，共同伸取某物 --->）
vi. for/with + sth 争辩；争论；竞争
vt. 主张
contention n.争辩，争论
contentious adj.有争议的
Despite what the officer said,the driver contended she was only driving at 30 mph. 不管警察说什么那个司机都争辩说自己的架车时速只有30英里。
2. extensive（向外伸展的 ex(=out) + tens(=stretch)）
adj.广大的；广泛的
extend v.扩展，扩大；伸（手、脚等）(ex出+tend伸展,趋向→伸出去→扩张)
extension n.延长，扩大
extent n.宽度，程度，范围；[律]<英>扣押令
extensively adv.广大地，广泛地
An extensive system of underground aquifers provides water in the Midwest. 大范围的地下蓄水层为中西部地区提供用水。
3. intensive（在...里拉长的 in(=in) + tens(=stretch)）
adj.强烈的；集中的；精深的；透彻的；加强语气，强调的
intensify v.加强
intensification n.激化，强化
intensity n.强烈；极度
intension n.强度
intense adj.强烈的，激烈的；热情的
I took a 2-day intensive course on how to use my new computer. 为学会使用我的新计算机，我参加了一个为期两天的强化培训课程。
4. ostensible（向上拉长的 os<ob(=over,against) + tens(=stretch)）
adj.表面上的，外表上的；面子上的
ostensibly adv.表面上
The ostensible reason for their divorce was "irreconcilable differences". 他们离婚的表面理由是“性格不和”。
5. ostentatious（向某物的反方向拉长的 os<ob(=against,over) + tent(=stretch)）
adj.卖弄的，夸耀的；豪华的，铺张的
ostentation n.夸耀，卖弄；虚饰 （os-(obs-) = in front of 在...之前；tent = to stretch 展开；-ation n. = the act 表行为 --> " the act of stretching one's belongings in front of others 在他人面前展示财物" -->）
ostentatiously adv.卖弄地
We want an elegant but not ostentatious wedding. 我们希望办一场高雅而不铺张的婚礼。
6. pretentious（向前伸展的 pre(=before) + tent(=stretch)）
adj.炫耀的，做作的；狂妄的
pretend v.做作，自负（pre- = before 在...之前；tend = to stretch 伸展 -->" to stretch one's mind before the public 在众人面前展开或夸张自己的想法" -->）
pretense n.虚假；做作
pretension n.自命，自称；做作；假装；借口；托词
pretender n.妄提要求者；伪装者
The people at the coutry club aren't pretentious at all. They're very nice !那个乡村俱乐部的人一点都不狂妄，他们很新切！
7. attend
v.出席，参加；（~to）致力于；护理；陪同，伴随；侍奉 *at<ad(=to)
The lectures were well attended. 听演讲的人很多。
attend to what others are sying 注意听别人说的话
have the honor of attending upon the Prince 很荣幸侍奉王子
My good luck attends you!祝你好运！
8. attendance
n.出席，出勒；出席人数；侍奉，照料 *at<ad(=to)
certificate of attendance 在学证明书
prize for regular attendance 全勒奖
attendance book 出勒簿
large/small attendance 出席人数多/少
in attendance upon the Queen 陪同女王
9. attention (at加强+tent伸展,趋向+ion表名词→伸展出去→注意;照料)
n.注意，注意力；（pl.）殷勤；照料；立正姿势；治疗 *at<ad(=to)
Attention,Mr.Roberts （用在商务文书、公文中）罗伯茨先生亲启
Attention,please! 各位请注意！
attract/draw attention 引起注意
listen with attention 倾听
Pay one's attentions to a lady 讨一位小姐的欢心
Attention! （口令）立正！缩略语：Shun!
receive immediate attention 得到紧急救治
10. attendant
n.侍从；出席者;(pl.)随行人员 adj.伴随的；侍候的，护理的 *at<ad(=to)
attendee n.出席者
the Prince and his attendants 王子及其侍从
famine and its attendant diseases 饥荒和紧随其至的疾病
old age and its attendant evils 老龄及紧随甚至的麻烦
11. attentive (at加强+tent伸展,趋向+ive……的→一再把脑袋向前伸（例如，我们见到老师都要向躬身问好；发现有吸引力的东西特别是看书时，我们都要下意识地伸头）→)
adj.注意的，留意的；专心的；体贴的 ；注意的,有礼貌的
attentively adv.注意地；周到地
attentive to one's studies 专心致志学习的
attentive to her young brother 关心她弟弟的
attentive audience 倾听的观众
12. detente
n.<法>紧张关系的缓和 *de(=down)
13. distend（dis- 散开，tend 伸，扩）
v.扩张，扩大；使膨胀，膨胀 *dis(=away)
distension /distention 膨胀
14. hypertension （hyper- 超高，tension 张力，压力；“血的压力过高”-->）
n.高血压 *hyper(=over,above,excessive)
15. hypotension (hypo在……下面,次等+tension压力[引申血压]→n.血压过低)
n.低血压 *hypo(=under,less)
16. intend （in- 入，tend 伸；“把心思伸向某事”-->打算做某事-->）
v.想要；计划，打算；意指 *in(=into)
intended adj.预谋的，故意的；（n.）已订婚者
Let me introduce you to my intended. 我向你介绍我的未婚妻。
17. intent （in- 入，tent(=tend)）
n.目标；意图；意味，意思 adj.（表情）热切的；（~ on ）专心致志的 *in(=into,intensive)
intently adv.专心地，专注地；热切地
shoot with intent to kill 故意开枪杀人
with good/evil (malicious) intent 善意地/恶意地
to all intents and purposes 事实上
intent on his work 埋头于他的工作的
intent on beautiful scenery 陶醉于美景的
18. intention （同上，-tion 名词后缀）
n.意向，意图，目标，目的 *in (=into,intensive)
with good intentions 善意地
without intention 无意中
with the intention of ~ing（打算做...）
well-intentioned/ill-intentioned 善意地/恶意地
19. intentional
adj.故意的，蓄谋的 *in (=into,intensive)
20. portend （por- = pro- 前，tend(=tent) 伸；出现在...之前的情况或事物-->）
v.预示（未来）；预先警告 *por<per(=through)
Black clouds portend a storm. 乌云预示着风雨即将来临。
21. portent （por- = pro- 前，tend 伸；“伸到前面”-->出现在前面，（某种情况或事物）出现在...之前-->）
n.（不祥的、大事件的）征兆，预兆；迹象；异常的人（或事物）
portentous adj.不祥的，凶兆的；令人惊讶的；自命不凡的
22. superintend
v.主管；监督；指挥 *super(=over),in(=into)
superintendence 主管；监督
23. superintendent
n.监督者，管理者；（企业，机关等的）负责人 *super(=over),in(=into)
superintendent of schools 教育局局长
superintendent of a revenue office 税务局局长
24. tend
v.看管，照料（把注意力伸向某人或某事-->）；倾向，趋向（伸向-->）
25. tendency (tend趋向+ence表名词→n.趋势,趋向)
n.倾向，趋势
strong upward tendency in oil shares 石油类股票的强劲上涨趋势
26. tendentious
adj.倾向性的，有偏见的；宣传性的
tendentious/tendencious reports 宣传性报道
27. tender （tend 伸-->伸出；“刚伸出（长出）的嫩芽”-->）
adj.（色彩、光线等）柔和的；柔弱的；年幼的，未成熟的；敏感的，容易受到伤害的，一触就痛的；棘手的；（肉）易咀嚼的，嫩的；亲切的，温柔的，体贴的 adv.温柔地，亲切地 n.看护人员；补给船；投标；法定货币；提出，提供 v.提出，提供；投标
tender green 嫩江绿
tender skin 娇嫩的皮肤
tender subject 棘手的问题，微妙的问题
tender loin （牛或猪）腰部的嫩肉
tender looks/care 和蔼的表情/温柔的照料
tender tender parents 体贴的父母
tender hearted 心肠软的，富于恻隐之心的
Love me tender. 温柔地爱我
tender his resignation to the president 向总统递交辞呈
28. tendon
n.筋，腱
29. tense（tense 伸，伸开-->拉紧）
adj.拉紧的；紧张的 v.使拉紧，使绷紧；使紧张 n.[语]时态
tensible（见上，-ible 可...的）n.可伸展的，可拉长的
tensity（见上，-ity 表情情况、性质）n.紧张，紧张度
faces tensed with anxiety 焦虑、紧张的面孔
tense atmosphere 紧张的气氛
He tensed his muscles for the effort. 他将自己的肌肉绷起来发力。
He's always tensed up before an exam. 他在考试前总是紧张。
30. tent （tent 伸；能够“伸开（张开）”的东西（如皮革、帆布等），用作掩盖、庇护之用-->）
n. 账篷，帐棚
词根词缀：-aceous, -acea, -aceae, -aceaen, -aceus
【来源及含义】Latin: a suffix; having the quality of, of the nature of, characterized by, belonging to, resembling
【相关描述】There are hunderds of words that utilize the -aceous suffix which are not shown here; however, the following will present important examples.
A suffix that forms adjectives and is used with technical combinations, especially in biological terms: "pertaining or belonging to, of the nature of, or characterized by; to be full of, to possess abundantly". The suffix -acea usually denotes "orders and classes in zoology" while the suffix -aceae usually denotes "orders and families in botany" and -aceaen is used to denote members of "orders of the animal kingdom".
【同源单词】acanthaceous, -aceous, alliaceous, ampullaceous, amygdalaceous, amylaceous
词根词缀：-al, -ial, -eal
【来源及含义】Latin: suffix; pertaining to, like, of the kind of, relating to, characterized by, belonging to; action of, process of
【同源单词】abacterial, abdominal, abdominal adhesion, abdominal aorta, abdominal aortic aneurysm, abdominal aortography
词根词缀：allotrio- , allotri-
【来源及含义】Greek: different, of or belonging to another; foreign, strange; abnormal; perverse
【相关词根词缀】 Related "foreign, strange" word families: barbar-; xeno-.
【同源单词】allotridontia, allotriogeustia, allotriolith, allotriomorphic, allotriophagia, allotriorhexia
词根词缀：-an, -ane
【来源及含义】Latin: a suffix that forms nouns; pertaining to, like; connected with, belonging to, resembling
【同源单词】American, amphibian, Chicagoan, crustacean, Cuban, cygnean
词根词缀：cras-, crastin-
【来源及含义】Latin: tomorrow, of tomorrow, belonging to tomorrow; delay, delaying, putting off until a later date
【同源单词】procrastinate, procrastinated, procrastinatingly, procrastination, procrastinative, procrastinatively
词根词缀：-ese
【来源及含义】Latin: suffix from -ensis, of, belonging to, from [a place]; originating in [a city or country]
【相关描述】Examples of -ese words include Milanese architect, Vietnamese people, with corresponding nouns meaning "native" or "inhabitant of" (a Viennese, the Japanese), "language of" (Chinese, Portuguese), or, by extension, "typical style" or "vocabulary of", as in journalese, bureaucratese, Johnsonese, New Yorkese".
【同源单词】academese, bureaucratese, Burmese, computerese, headlinese, journalese
词根词缀：-ian
【来源及含义】Latin: suffix form of -an from -ianus, a modifier of the main word to which it is attached: belonging to, coming from, being involved in, or being like something
【相关描述】Appearing in such words as comedian, egalitarian, Bostonian, Italian, Smithsonian, mathematician, Alabamian, Californian, Arizonian, and Canadian. It is attached to the root of common or proper nouns with the meanings "of, pertaining to, from", or "like" the proper name appearing in the stem.
【同源单词】abecedarian, academician, acanthopterygian, acararian, acoustician, aeolian
词根词缀：-ile, -il
【来源及含义】Latin: suffix; ability to, capable of, suitable for; pertaining to, like, belonging to, tending to
【同源单词】agile, docile, domicile, facile, fertile, fragile
词根词缀：indigen-
【来源及含义】Latin: belonging to a country; born in a country; native to a geographical area
【同源单词】indigen, indigenization, indigenous, indigenously, indigenousness