英语中，表“单数”和“复数”的单词single和plural都源自拉丁语。
【英语】single[ˈsiŋɡl]adj.1. 单一[独, 式]的; 个别的2. 单身的; 一人用的3. 一人对一人的4. 专一的; 纯真的; 诚实的5. 唯一的, 无比的6. [英](酒等)味淡的; 力弱的7. 【植】单瓣的8. 【无】单次的, 单的9. 单程的
in single file一路纵队
the single state独身状态
a single bed单人床
a single tulip单瓣郁金香
devote oneself with a single mind to ...全心全意献身于...
with an eye single to一心关注
拆解：sin gle。
请家长朋友大概了解词源：
single (adj.)
early 14c., "unmarried," from Old French sengle, sangle "alone, unaccompanied; simple, unadorned," from Latin singulus "one, one to each, individual, separate" (usually in plural singuli "one by one"), from PIE *semgolo‑, suffixed (diminutive?) form of root *sem- (1) "one; as one, together with."
重点记忆：这里的sin-最终源自PIE（原始印欧语）表“一”的词根*sem-。对应英语单词same中的sam-。
【英语】same[seɪm]adj. 同一的; 上述的; 同样的; 无变化的adv. 同样地
拆解：sam e。
词源：
ame (adj.)
"identical, equal; unchanging; one in substance or general character," from Proto-Germanic *samaz "same" (source also of Old Saxon, Old High German, Gothic sama, Old High German samant, German samt "together, with," Gothic samana "together," Dutch zamelen "to collect," German zusammen "together"), from PIE *samos "same," from suffixed form of root *sem- (1) "one; as one, together with."
在记忆plural前一定要先熟悉plus。
【英语】plus[plʌs]prep. 加；加上
4 plus 3 equals 7.四加三等于七。
adj.1. 附加的；受欢迎的
a plus factor有利因素
2. 超过的（年龄）
All the children here are 10 plus.
这些孩子年龄都在10岁或者10岁以上。
3. 略大的；超过标准的
Her mark was B plus。
她的分数B 。
4. 正的
the plus sign正号
词源：plus (n., adj.)
1570s, the oral rendering of the arithmetical sign , also "more by a certain amount" (correlative to minus), from Latin plus "more, in greater number, more often" (comparative of multus "much"), altered (by influence of minus) from *pleos, from PIE root *pele- (1) "to fill" (see poly-). The plus sign itself has been well-known at least since late 15c. and is perhaps an abbreviation of Latin et (see et cetera).
很明显，plural是plus的形容词。
【英语】plural[ˈpluərəl]adj.1. 【语】复数的, 多于一个的2. 由复数组成的, 包含复数的
a plural noun复数名词
plural livings【宗】兼俸
plural marriage一夫多妻; 一妻多夫
plural vote一人多选区投票(权)
adv.n. 【语】复数; (词的)复数形式; 复数形式的单词 plurally
拆解：plur al。
请家长朋友牢记：英语、法语、德语、意大利语、西班牙语中的-al都源自拉丁语形容词后缀-alis。
只要您愿意，就可以掌握相应的拉丁语单词。
【拉丁语】pluralis：pluralis, pluralis, plural adj. plural;
拆解：plur alis。
我们在学习拉丁语不规则动词esse时专门介绍了：esse是由词根es-（对应英语的be）和动词不定式后缀-se(接元音时变化为-re)构成。
请特别注意：拉丁语中，s在元音之间时通常变化为r。
所以，词根es-在接元音时会变化为er-。
所以，esse在它的未完式时和将来式中都变化为-er。
请大概了解：拉丁语和它的后代法语、意大利语、西班牙语中，动词有专门表“将来”的将来式(future tense)。
而同属于印欧语日耳曼语族西日耳曼语支的英语、德语、荷兰语，动词都没有“将来式”。
英语、德语、荷兰语的所谓“将来时态”都是通过变通的方式实现的，汉语中是通过增加副词实现的。
我认为，家长朋友和孩子一起利用英语原版教材实现英语快速入门是极佳的学习方法。
上一节，我们介绍了《对孩子的人生至关重要的18种元素》并重点学习了其中6个以-um结尾的化学元素名称。
这一节，我们重点学习3个以-gen，2个以-ine结尾的化学元素名称。
【英语】hydrogen[ˈhaɪdrədʒ(ə)n]n. 〈化〉氢
拆解：hydro gen。
词源：hydrogen (n.)
colorless, gaseous element, 1791, hydrogene, from French hydrogène (Modern Latin hydrogenium), coined 1787 by G. de Morveau, Lavoisier, Berthollet, and Fourcroy from Greek hydr-, stem of hydor "water" (from suffixed form of PIE root *wed- (1) "water; wet") French -gène "producing" (see -gen).
So called because it forms water when exposed to oxygen. Nativized in Russian as vodorod; in German, it is wasserstoff, "water-stuff." An earlier name for it in English was Cavendish‘s inflammable air (1767). Hydrogen bomb first recorded 1947; shortened form H-bomb is from 1950.
重点记忆：
1、 hydr-源自希腊语表“水”的词根。
2、 gen-源自法语表“基因”的单词gène，最终经由希腊语源自PIE（原始印欧语）*gene- "give birth, beget"。
【英语】oxygen[ˈɔksɪdʒ(ə)n]n. 氧，氧气
拆解：oxy gen。
词源：oxygen (n.)
gaseous chemical element, 1790, from French oxygène, coined in 1777 by French chemist Antoine-Laurent Lavoisier (1743-1794), from Greek oxys "sharp, acid" (from PIE root *ak- "be sharp, rise (out) to a point, pierce") French -gène "something that produces" (from Greek -genēs "formation, creation;" see -gen).
请大概了解：源自希腊语的oxy-对应源自拉丁语的ac-（注意不是ag-的读音变化），表“尖，酸”。
认识拉丁语后缀-id的小朋友都可以不费吹灰之力掌握英语、法语、德语、意大利语、西班牙语表“酸”的单词。
【英语】acid[‘æsɪd]n. 酸; 讥刺; 有酸味的东西; 迷幻药adj. 酸的, 有酸味的; 尖酸刻薄的; 酸性的; 敏锐的; 讽刺的
拆解：ac id。
【英语】nitrogen[ˈnaitrədʒən]n.【化】氮(7号元素, 符号N)
nitrogen monoxide一氧化二氮
nitrogen fixer(土壤中的)固氮微生物
nitrogen narcosis氮麻醉(血液中高压氮引起的麻醉状态, 深水潜水时可能发生)
拆解：nitro gen。
词源：nitrogen (n.)
colorless, odorless gaseous element, 1794, from French nitrogène, coined 1790 by French chemist Jean Antoine Chaptal (1756-1832), from Greek nitron "sodium carbonate" (see nitro-) French gène "producing," from Greek -gen "giving birth to" (see -gen). The gas was identified in part by analysis of nitre. An earlier name for it was mephitic air (1772), and Lavoisier called it azote (see azo-). It forms about 78% of the weight of the Earth‘s atmosphere. Related: Nitrogenic; nitrogenous.
前面，我们介绍了：英语的化学元素名词有很多用到-(i)um。
这里，我们又遇到另一个常用后缀-ine。 在fluorine和chlorine中，都用到-ine。
【英语】fluorine[ˈflu(ː)əriːn]n. 【化】氟(9号元素, 符号F)
拆解：flu or ine。
词源：fluorine (n.)
non-metallic element, 1813, coined by English chemist Sir Humphry Davy from fluorspar ("calcium fluoride," modern fluorite), the late 18c. name of the mineral where it was first found (see fluor) chemical suffix -ine (2). Not isolated until 1886. Related: Fluorinate; fluorination.
【英语】fluor[ˈflu(ː)ɔː]n. 氟石, 荧石
拆解：flu or。
fluor (n.)
1660s, an old chemistry term for "minerals which were readily fusible and useful as fluxes in smelting" [Flood], from Latin fluor, originally meaning "a flowing, flow," from fluere "to flow, stream, run, melt" (see fluent). Said to be from a translation of the German miners‘ name, flusse. Since 1771 applied to minerals containing fluorine, especially calcium fluoride (fluorspar or fluorite).
请家长朋友特别注意：英语中以-or结尾的单词绝大多数都源自拉丁语。
请顺便熟悉英语单词color（颜色），favor（赞成），humor（幽默），tumor（肿瘤），rumor（谣言），mirror（镜子）。
请牢记：拉丁语中的flu-表“流”。
【拉丁语】flumen：flumen, fluminis n. n. river, stream; any flowing fluid; flood; onrush;
拆解：flu men(名词后缀)。
【英语】flumen[ˈfluːmən]n.(pl.-mina)水流, 波
flumen pilorum毛流, 体毛分布腺
拆解：flu men。
【英语】influence[ˈɪnflʊəns]n.1. （常与on连用）影响力；感化力
My teacher‘s influence made me study science at college.
由于我老师的影响，我上大学学了理科。
Many a woman has had civilizing influence upon her husband.
许多妇女对其丈夫有影响。
2. （常与over, with连用）权力；势力
Will you exercise your influence on my behalf?
你愿意运用你的权力给我帮忙吗？
vt. -enced, -encing 影响
My teacher influenced my decision to study science.
我的老师对我学理科的决定起了影响作用。
拆解：in flu ence（名词后缀）。
这就是说，认识后缀-or和-ine的小朋友只要重点记忆flu-就可以轻松掌握英语单词fluorine。
【英语】chlorine [ˈklɔːriːn]n.【化】氯(17号元素, 符号Cl)
chlorine water氯水(漂白液)
拆解：chlor ine。
词源：chlorine (n.)
nonmetallic element, the name coined 1810 by English chemist Sir Humphry Davy from Latinized form of Greek khlōros "pale green" (from PIE root *ghel- (2) "to shine," with derivatives denoting "green" and "yellow") chemical suffix -ine (2). Named for its color. Discovered 1774, but known at first as oxymuriatic acid gas, or dephlogisticated marine acid.
重点记忆chlor-源自希腊语表“淡绿”的词根。
一定要牢记：英语中希腊语源单词中的ch通常读汉语拼音的k。
请牢记：chem-表“化学”，加上-ist就是chemist（化学家），再加上-ry（后缀-ery的变化）就是chemistry（化学）。
请牢记：所有的复杂单词都不用（也不可以）死记硬背。