新目標(biāo)人教版初中八年級上冊英語語法匯總

1、精品文檔 新目標(biāo)人教版學(xué)校八班級上冊英語語法匯總1) leave的用法1.“l(fā)eave+地點表示“離開某地。例如When did you leave Shanghai?你什么時候離開上海的 2.“l(fā)eave for+地點表示“動身去某地。例如 Next Friday, Alice is leaving for London. 下周五愛麗斯要去倫敦了。 3.“l(fā)eave+地點+for+地點表示“離開某地去某地。例如 Why are you leaving Shanghai for Beijing?你為什么要離開上海去北京2) 情態(tài)動詞should“應(yīng)當(dāng)學(xué)會使用 should作為情態(tài)動詞用經(jīng)常表示

2、意外、驚異、不能理解等有“竟會的意思 例如 How should I know? 我怎么知道 Why should you be so late today?你今日為什么來得這么晚 should有時表示應(yīng)當(dāng)做或發(fā)生的事例如 We should help each other.我們應(yīng)當(dāng)相互掛念。 我們在使用時要留意以下幾點 1. 用于表示“應(yīng)當(dāng)或“不應(yīng)當(dāng)?shù)母拍?。此時常指長輩訓(xùn)練或責(zé)怪晚輩。例如 You should be here with clean hands. 你應(yīng)當(dāng)把手洗潔凈了再來。2. 用于提出意見勸導(dǎo)別人。例如 You should go to the doctor if you f

3、eel ill. 假設(shè)你感覺不舒適你最好去看醫(yī)生。3. 用于表示可能性。should的這一用法是考試中經(jīng)常消滅的考點之一。例如 We should arrive by supper time. 我們在晚飯前就能到了。 She should be here any moment. 她隨時都可能來。3) What.? 與 Which.?1. what 與 which 都是疑問代詞都可以指人或事物但是what僅用來詢問職業(yè)。如 What is your father? 你父親是干什么的 該句相當(dāng)于 What does your father do? What is your father's

4、 job? Which 指代的是特定范圍內(nèi)的某一個人。如-Which is Peter? 哪個是皮特-The boy behind Mary. 瑪麗背后的那個男孩。2. What.?是泛指所指的事物沒有范圍的限制而 Which.?是特指所指的事物有范圍的限制。如What color do you like best? 你最寵愛什么顏色 ( 全部顏色)Which color do you like best, blue, green or yellow? 你最寵愛哪一種顏色(有特定的范圍)3. what 與 which 后都可以接單、復(fù)數(shù)名詞和不行數(shù)名詞。如Which pictures are

5、from China? 哪些圖片來自中國4) 頻度副詞的位置 1.常見的頻度副詞有以下這些 always總是始終 usually通常 often經(jīng)常經(jīng)常sometimes有時候never從不2.頻度副詞的位置 a.放在連系動詞、助動詞或情態(tài)動詞后面。如 David is often arrives late for school. 大衛(wèi)上學(xué)經(jīng)常遲到。 b.放在行為動詞前。如 We usually go to school at 7:10 every day. 我們每天經(jīng)常在710去上學(xué)。 c.有些頻度副詞可放在句首或句尾用來表示強調(diào)。如 Sometimes I walk home, somet

6、ime I rides a bike. 有時我步行回家有時我騎自行車。3.never放在句首時主語、謂語動詞要倒裝。如Never have I been there. 5) every day 與 everyday 1. every day 作狀語譯為“每一天。如 We go to school at 7:10 every day. 我們每天710去上學(xué)。 I decide to read English every day.我打算每天讀英語。 2. everyday 作定語譯為“日常的。 She watches everyday English on TV after dinner.她晚飯后

7、在電視上看日常英語。 What's your everyday activity? 你的日常活動是什么6) 什么是助動詞1.幫助主要動詞構(gòu)成謂語動詞詞組的詞叫助動詞Auxiliary Verb。被幫助的動詞稱作主要動詞Main Verb。助動詞自身沒有詞義不行單獨使用例如He doesn't like English. 他不寵愛英語。doesn't是助動詞無詞義like是主要動詞有詞義2.助動詞幫助主要動詞完成以下功用可以用來a. 表示時態(tài)例如He is singing. 他在唱歌。He has got married. 他已結(jié)婚。b. 表示語態(tài)例如He was sen

8、t to England. 他被派往英國。c. 構(gòu)成疑問句例如Do you like college life? 你寵愛高校生活嗎Did you study English before you came here? 你來這兒之前學(xué)過英語嗎d. 與否認副詞not合用構(gòu)成否認句例如I don't like him. 我不寵愛他。e. 加強語氣例如Do come to the party tomorrow evening. 明天晚上肯定來參與晚會。He did know that. 他確實知道那件事。3.最常用的助動詞有be, have, do, shall, will, should,

9、would7) forget doing/to do與remember doing/to do1.forget to do 遺忘要去做某事。 (未做) forget doing 遺忘做過某事。 (已做) The light in the office is still on. He forgot to turn it off. 辦公室的燈還在亮著它遺忘關(guān)了。(沒有做關(guān)燈的動作) He forgot turning the light off. 他遺忘他已經(jīng)關(guān)了燈了。( 已做過關(guān)燈的動作) Don't forget to come tomorrow.別忘了明天來。(to come動作未做

10、) 典型例題- The light in the office is still on.- OhI forgot_.A. turning it off B. turn it off C. to turn it off D. having turned it off 答案C。由the light is still on 可知燈亮著即關(guān)燈的動作沒有發(fā)生因此用forget to do sth.而forget doing sth 表示燈已經(jīng)關(guān)上了而自己遺忘了這一事實。此處不符合題意。 2.remember to do 記得去做某事 (未做)remember doing 記得做過某事 (已做)Remem

11、ber to go to the post office after school. 記著放學(xué)后去趟郵局。Don't you remember seeing the man before?你不記得以前見過那個人嗎? 8) It's for sb.和 It's of sb.1.for sb. 常用于表示事物的特征特點表示客觀形式的形容詞如easy, hard, difficult, interesting, impossible等It's very hard for him to study two languages. 對他來說學(xué)兩門外語是很難的。2.of sb

12、 的句型一般用表示人物的性格品德表示主觀感情或態(tài)度的形容詞如good, kind, nice, clever, foolish, right。It's very nice of you to help me. 你來掛念我你真是太好了。3.for 與of 的區(qū)分方法用介詞后面的代詞作主語用介詞前邊的形容詞作表語造個句子。假設(shè)道理上通順用of不通那么用for。如You are nice. (通順?biāo)詰?yīng)用of)。He is hard. (人是困難的不通因此應(yīng)用for。)9) 對兩個句子的提問新目標(biāo)英語在命題中有將對句子劃線提問這一題型取消的趨勢現(xiàn)在實行的作法是對一個句子進行自由提問。例如句子

13、The boy in blue has three pens.提問1.Who has three pens? 2.Which boy has three pens? 3.What does the boy in blue have?4.How many pens does the boy in blue have?很明顯同學(xué)多了更多的答復(fù)角度也表達了考試的機敏性。再如句子He usually goes to the park with his friends at 8:00 on Sunday.提問1.Who usually goes to the park with his friends

14、at 8:00 on Sunday? 2.Where does he usually go with his friends at 8:00 on Sunday? 3.What does he usually do with his friends at 8:00 on Sunday? 4.With whom does he usually go to the park at 8:00 on Sunday? 5.What time does he usually go to the park with his friends on Sunday? 6.When does he usually

15、go to the park with his friends?10) so、such與不定冠詞的使用1.so與不定冠詞a、an連用結(jié)構(gòu)為“so+形容詞+a/an+名詞。如 He is so funny a boy. Jim has so big a house. 2.such與不定冠詞a、an連用結(jié)構(gòu)為“such+a/an+形容詞+名詞。如 It is such a nice day. That was such an interesting story.11) 使用-ing分詞的幾種狀況1.在進行時態(tài)中。如 He is watching TV in the room. They were

16、dancing at nine o'clock last night.2.在there be結(jié)構(gòu)中。如 There is a boy swimming in the river.3.在have fun/problems結(jié)構(gòu)中。如 We have fun learning English this term. They had problems getting to the top of the mountain.4.在介詞后面。如 Thanks for helping me. Are you good at playing basketball. 5.在以下結(jié)構(gòu)中 enjoy doin

17、g sth 樂于做某事 finish doing sth 完成做某事 feel like doing sth 想要做某事 stop doing sth 停止做某事 forget doing sth 遺忘做過某事 go on doing sth 連續(xù)做某事 remember doing sth 記得做過某事 like doing sth 寵愛做某事 keep sb doing sth 使某人始終做某事 find sb doing sth 覺察某人做某事 see/hear/watch sb doing sth 看到/聽到/觀看某人做某事 try doing sth 試圖做某事 need doing

18、 sth 需要做某事 prefer doing sth 寧愿做某事 mind doing sth 介意做某事 practice doing sth 練習(xí)做某事 be busy doing sth 忙于做某事 can't help doing sth 禁不住做某事 miss doing sth 錯過做某事12) 英語中的“單數(shù)1.主語的第三人稱單數(shù)形式即可用“he, she, it代替的。如 he, she, it my friend, his teacher, our classroom, Tom, Mary's uncle 2.名詞有單數(shù)名詞和復(fù)數(shù)名詞。如 man 單數(shù)-me

19、n復(fù)數(shù) banana單數(shù)-bananas復(fù)數(shù)3.動詞有原形第三人稱單數(shù)形式-ing分詞過去式過去分詞。如 go-goes-going-went-gone work-works-working-worked-worked watch-watches-watching-watched-watched 當(dāng)主語為第三人稱單數(shù)的時候謂語動詞必需用相應(yīng)的第三人稱單數(shù)形式。如 The boy wants to be a sales assistant. Our English teacher is from the US. Their daughter makes her breakfast all by

20、herself. 13) 名詞的復(fù)數(shù)構(gòu)成的幾種形式名詞復(fù)數(shù)的構(gòu)成可分為規(guī)章變化和不規(guī)章變化兩種。I 名詞復(fù)數(shù)的規(guī)章變化 1.一般在名詞詞尾加-s。如pear-pears hamburger-hamburgers desk-desks tree-trees 2.以字母-s, -sh, -ch, -x結(jié)尾的名詞詞尾加-es。如 class-classes dish-dishes watch-watches box-boxes 3.以字母-o結(jié)尾的某些名詞詞尾加-es。如 potato-potatoes tomato-tomatoes Negro-Negroes hero-heroes 4.以輔音字

21、母加-y結(jié)尾的名詞將-y變?yōu)?i,再加-es。如 family-families dictionary-dictionaries city-cities country-countries 5.以字母-f或-fe結(jié)尾的名詞將-f或-fe變?yōu)?v再加-es。如half-halves leaf-leaves thief-thieves knife-knives self-selveswife-wives life-lives wolf-wolves shelf-shelves loaf-loaves但是scarf-scarves(fes) roof-roofs serf-serfs gulf-gu

22、lfs chief-chiefsproof-proofs belief-beliefs II 名詞復(fù)數(shù)的不規(guī)章變化 1.將-oo改為-ee。如foot-feet tooth-teeth 2.將-man改為-men。如man-men woman-women policeman-policemen postman-postmen3.添加詞尾。如child-children 4.單復(fù)數(shù)同形。如sheep-sheep deer-deer fish-fish people-people5.表示“某國人的單、復(fù)數(shù)變化。即“中日瑞不變英法變其它國把-s加后面。如Chinese-Chinese Japanes

23、e-Japanese Swiss-Swiss Englishman-Englishmen Frenchman-Frenchmen American-Americans Australian-Australians Canadian-Canadians Korean-Koreans Russian-Russians Indian-Indians6.其它。如mouse-mice apple tree-apple trees man teacher-men teachers 14) 雙寫最終一個字母的-ing分詞學(xué)校階段常見的有以下這些 1.letletting 讓 hithitting 打、撞 c

24、utcutting 切、割 getgetting 取、得到 sitsitting 坐 forgetforgetting 遺忘 putputting 放 setsetting 設(shè)置 babysitbabysitting 臨時受雇照看嬰兒2.shopshopping 購物 triptripping 絆 stopstopping 停止 dropdropping 放棄 3.traveltravel(l)ing 旅游 swimswimming 游泳 runrunning 跑步 digdigging 挖、掘 beginbeginning 開頭 preferpreferring 寧愿 planplannin

25、g 方案15) 確定句變否認句及疑問句要變化的一些詞1.some變?yōu)閍ny。如 There are some birds in the tree. There aren't any birds in the tree. 但是假設(shè)在表示請邀請、懇求的句子中some可以不變。如 Would you like some orange juice? 與此相關(guān)的一些不定代詞如something, somebody等也要進行相應(yīng)變化。2.and變?yōu)閛r。如 I have a knife and a ruler. I don't have a knife or a ruler.3.a lot

26、 of (=lots of)變?yōu)閙any或much。如 They have a lot of friends.可數(shù)名詞 They don't have many friends. There is lots of orange in the bottle.不行數(shù)名詞 There isn't much orange in the bottle. 4.already變?yōu)閥et。如 I have been there already. I haven't been there yet.16) in與afterin 與 after 都可以表示時間但二者有所區(qū)分。1.in 經(jīng)常用

27、于將來時的句子中以現(xiàn)在為起點表示將來一段時間。如 He will leave for Beijing in a week. 一周后他會動身去北京。2.after 經(jīng)常用于過去時的句子中以過去為起點表示過去一段時間。如 He left for Beijing after a week. 一周后他動身去了北京。不過假設(shè)after后跟的是具體的時刻它也可用于將來時。如 We will finish the work after ten o'clock. 十點后我們會完成工作的。 3.留意區(qū)分以下的in的用法。 I'll visit him in a week. 一周后我會去訪問他。

28、I'll visit him twice in a week. 一周內(nèi)我會去訪問他兩次。17) 不定冠詞a與an的使用1.a 用在以輔音音素開頭的單詞前。如 There is a "b" in the word "book". 單詞book中有個字母b。 類似的字母還有c, d, g, j, k, p, q, t, u, v, w, y, z。 She has a small knife. 她有一把小刀。2.an 用于以元音音素開頭的單詞前。如 There is an "i" in the word "onion&q

29、uot;. 單詞onion中有個字母i。 類似的字母還有a, e, f, h, l, m, n, o, r, s, x。 Do you have an umbrella? 你有一把雨傘嗎3.以元音字母開頭的單詞前面不肯定都用an以輔音字母開頭的單詞前面也不肯定都用a。如a useful book a universe a one-letter word an hour an uncle an umbrella an honest person 18) 如何表達英語中的“穿、戴英語中表示“穿、戴的表達方法有好幾種常見的有以下這些1、put on 主要表達“穿的動作。如 He put on his

30、 coat.他穿上了他的外套。 You'd better put on your shoes.你最好穿上你的鞋子。2、wear 主要表示“穿、戴的狀態(tài)。如 The old man wears a pair of glasses.老人戴著一副眼鏡。 The girl is wearing a red skirt.那女孩穿著一條紅色的短裙。3、dress 可作及物動詞有“給.穿衣的意思后接“人而不是“衣服。如 Please dress the children right now.請馬上給孩子們穿上衣服。 dress 也可作不及物動詞表示衣著的習(xí)慣。如 The woman always d

31、resses in green.那位婦女總是穿綠色的衣服。4、be in 表示穿著的狀態(tài)。如 John is in white today.約翰今日穿白色的衣服。 The man in black is a football coach.19) a little, a few 與 a bit (of)a little, a few 與 a bit (of) 都有“一些、少量的意義。他們的區(qū)分在哪里呢1. a little 意為“一些、少量后接不行數(shù)名詞。如 There is a little water in the bottle. 瓶子里有一點水。 還可以接形容詞。如 He is a lit

32、tle shy. 他有些大方。2. a few 意為“一些、少數(shù)后接復(fù)數(shù)的可數(shù)名詞。如 There are a few people in the room. 房間里有一些人。3. a bit 意為“一點兒后接形容詞。如 It's a bit cold. 有點冷。 a bit of 后接不行數(shù)名詞。如 He has a bit of money. 他有一點兒錢。 4. a little 表確定意義little 表否認意義a few 表確定意義few 表否認意義。如 There is a little soda in the glass. 杯子里有一點兒汽水。 There is litt

33、le soda in the glass. 杯子里幾乎沒有汽水了。 I have a few Chinese friends. 我有一些中國伴侶。 Few people like him. 幾乎沒有人寵愛他。5. a little = a bit of, 后接不行數(shù)名詞 a little = a bit = a little bit = kind of, 后接形容詞意為“有點兒。20) 關(guān)于like的用法like 可以作動詞也可以作介詞。1、like 作動詞表示一般性的“愛好、寵愛有泛指的含義。如 Do you like the color?你寵愛這種顏色嗎 like 后可接不定式like t

34、o do sth也可接動詞的-ing分詞like doing sth有時意思不盡相同。如 She likes eating apples.她寵愛吃蘋果。習(xí)慣 She likes to eat an apple.她寵愛吃一粒蘋果。平常不寵愛吃 like 與 would 連用后接不定式表示愿望或客氣的懇求。如 Would you like a cup of tea?您情愿喝杯茶嗎 “寵愛某人做某事可以用結(jié)構(gòu)“l(fā)ike sb to do sth/doing sth。如 They all like me to sing/singing English songs.他們都寵愛我唱英文歌。2、like 作

35、介詞可譯成“像.。如 She is friendly to us like a mother.她對我們友好就像母親一樣。 It looks like an orange.它看起來像個桔子。3、區(qū)分以下句子 A. What does he look like? B. What is he like? A句譯為“他長相如何指一個人的外貌特征而B句譯為“他人怎么樣指人的性格特點。C. The boy like Peter is over there. D. A boy like Peter can't do it.A句指外貌相像而D句指性格相像。21) stop to do sth 與 st

36、op doing sth1. stop to do sth 意為“停下來去做某事。如 The students stop to listen to their teacher. 同學(xué)們停下來去聽他們老師講話。 2. stop doing sth 意為“停止做某事。如 The students stopped talking. 同學(xué)們停止了談話。 與它們相反的句式是go on to do sth “連續(xù)做某事與剛剛一事不同和 go on doing sth “連續(xù)做某事與剛剛同一件事。如He finishes his homework and goes on to study English.

37、他完成了作業(yè)接著連續(xù)去念英語。They went on playing games. 他們連續(xù)玩玩耍。22) tell, speak, say 與 talk 1. tell 意為“告知、表達指某人把某一件事、一條信息傳送給別人或表達一件事。如 He tells me that he wants to be a teacher. 他告知我說他想成為一位老師。 Father always tells interesting stories to us. 爸爸總是給我們講好玩的故事。 tell sb sth 意為“告知某人某事。如 He told me something about his pas

38、t. 他告知我一些他的往事。 tell sb to do sth 意為“告知某人去做某事。如 David told his son to do the homework. 大衛(wèi)要他的兒子去做作業(yè)。 2. speak 意為“說話、講話后面主要接語言。如 He can speak English and a little Chinese. 他能講英語和一點漢語。 speak to 意為“和.講話、談話。如 Can I speak to Mr Zhang? 我能和張先生講話嗎 speak of 意為“提到、說起。如 The book speaks of my hometown. 那本書提到我的家鄉(xiāng)。

39、 3. talk 意為“談話、講話假設(shè)只有一方對另一方說話時一般用 talk to假設(shè)雙方或多方交談多用 with。如 Please talk to him right now. 請馬上同他談話。 He is talking with his friend. 他在和伴侶交談。 talk about 意為“談?wù)?。如 They are talking about the movie. 他們在談?wù)撃遣侩娪啊?have a talk with 意為“與.交談。如 Can I have a talk with you? 我可以和你交談嗎 4. say 意為“說。如 Can you say it in

40、English once more? 你能用英語再說一遍嗎 say to 意為“對.說。如 He said to his students that they would have a test. 他對他的同學(xué)說他們將有一個測試。 It is said that. 意為“據(jù)說。如 It is said that he could stay under the water for a long time. 據(jù)說他能呆在水里很長時間。 23) Excuse me! 與 I'm sorry! 1. Excuse me! 意為“打攪了對不起一般是為了與生疏人搭話或者要打斷對方所說做的事。如 E

41、xcuse me, is there a hotel in the neighborhood? 請問四周有旅館嗎 Excuse me, could I say something? 打攪一下我能說一些嗎 2. I'm sorry! 意為“對不起表示賠禮。如 I'm sorry, Mr Zhang. I won't do it again. 對不起張先生。我不會這么做了。 24) 表示時間的 in、on 與 at in, on 與 at 都可以和表示時間的詞組連用。 1. in 表示時間的一段或較長的時間。如 in the morning 在上午 in May, 2021

42、 在2021年五月 in a week 在一周之內(nèi)后 It's Sunday, I can finish it in two days. 現(xiàn)在是星期天我能在兩天后完成。星期二 Rome was not built in a day. 羅馬不是在一天內(nèi)建起來的。 2. on 主要指在具體的一天。如 on Sunday 在星期天 on May Day 在“五一節(jié) on a hot afternoon 在一個酷熱的下午 He arrived in Beijing on April 26,2021. 他于2021年4月26日到達北京。 3. at 表示時間的一點或比較短的時間。如 at 8:0

43、0 在八點 at noon 在中午 I always get up at 6:00 every morning. 我總是每天早晨六點起床。 It's always warm at this time of year. 每年的這個時候總是溫存的。25) Other及其用法Other 及其相近的詞組如 others, the other, the others, another, any other 等始終是中同學(xué)伴侶們比較困擾的問題平常的考試、作業(yè)中經(jīng)常出錯。下面是它們的一些用法1、other 指其余的人或物全部格是 other's復(fù)數(shù)形式是 othersthe other 指“

44、兩個人或物中的另一個其復(fù)數(shù)形式是 the othersothers 相當(dāng)于“other + 名詞所以不能充當(dāng)定語修飾名詞。others指整體中去掉一局部后剩余的局部但不是全部的即 some.others 一些.其余的人.。the others 強調(diào)整體中除去一局部后剩余的全部即some.the others.2、another 泛指三個以上的不定數(shù)目中的“另外一個。由 an 和 other 合并構(gòu)成所以不能和冠詞連用。another 修飾單數(shù)名詞比方another pencil. 3、any other 指除去本身以外的“任何其他的人或物后面要用名詞的單數(shù)形式。 26) look 短語 常見的

45、look短語有以下這些 1.look at 朝.看 Please look at the map of China. 請看中國地圖。(look at=have a look at)2.look for 查找 The old man is looking for his dog. 老人在查找他的狗。 3.look like 看起來像 Nancy looks like her mother. 南希看起來像她母親。 4.look the same 看上去一樣 Li Ping and Li Jing look the same. 李萍和李晶看上去一樣。 5.look up 查找Please look

46、up the word in the dictionary. 請在詞典中查找這個單詞。6.look over 認真檢查 The doctor looked over Mary carefully. 醫(yī)生認真檢查了瑪麗。7.look after 照看照看 You must look after your old father. 你必需照看你的老父親。8.look around 處處查找、查看 We looked around, but we found nothing strange. 我們四處查看但是我們沒有覺察驚異的東西。 27) tooalso與either 1.too用于確定句和疑問句一

47、般放在句尾其前常加逗號。如 We are in the same school, too. 我們也在相同的學(xué)校。 Do you play soccer every day, too? 你也每天踢足球嗎 2.also用于確定句和疑問句一般位于實義動詞前、be動詞后。如 Sandra is also a Korean student. Sandra 也是一個韓國同學(xué)。 3.either用于否認句一般放在句末。如 They don't know the answer, either. 她們也不知道答案。 4.as well as也有“也的意思。如 We have great mushroom

48、 pizza as well as soda. He is a happy boy as well. 28) hard與hardly 1.hard既可作形容詞也可作副詞。如 It's a hard(adj.) question. (=difficult) 這是一個難的問題。 The boy studies very hard(adv.). 那男孩學(xué)習(xí)格外努力。 句子結(jié)構(gòu)It's hard for sb to do sth 做某事對某人來說是難的。如 It's hard for him to finish the work. 完成那項工作對他來說很難。 留意區(qū)分hard

49、work 困難的工作 work hard 努力工作 2.hardly是頻度副詞表示否認的意思。=almost not通常用在形容詞、副詞和動詞之前。如 I can hardly see it. 我?guī)缀蹩床坏剿?29) sometime,sometimes,some time與some times 1.sometime是時間副詞指不確定的將來或過去某一點時間某時候或任何時候不指一段時間。如 We'll go to Beijing sometime next month. 我們下個月某一時候會去北京。 2.sometimes是頻度副詞指“有時、“不時的意思=at times。如 Sometimes I get up very late on Sunday morning. 有時候我在星期天早晨起得很晚。 3.some time是名詞詞組指一段時間一些時間或假設(shè)干時間。如 It took him some time to finish the book. 她花了一些時間去完成作業(yè)。 4.some times指“幾次。如 He met the woman s