资源简介 九年级Unit2 Section A 练习题一、单项选择1.—Do you know ________ red stands for good luck in China —Sure.A.how B.where C.that D.what2.Leo didn’t tell us if he ________ the meeting. If he ________ to come, I’m sure he will call me first.A.will attend, will decide B.would attend, decidesC.would attend, will decide D.attends, decides3.—The project is so difficult for your cousin.—Yes, I am wondering ________.that he will finish it on timeB.whether he can finish it by himselfC.how could I help him outD.can I do anything necessary for him4.—Jim, the new term starts today. I wonder ________.—I’m not so sure. But I heard that it is an experienced teacher.what our chemistry teacher is likeB.what is our chemistry teacher likeC.where our chemistry teacher isD.where is our chemistry teacher5.—Can you tell me _________ —Yes. The American writer Ernest Hemingway wrote it.A.who wrote the story B.when the story happenedC.where the writer is from D.why people like the story6.—Could you tell me ________ —It’s next to the post office.A.what the supermarket is B.where the supermarket isC.what was the supermarket was D.where the supermarket was7.Could you please tell me __________ A.why were you in such a hurry B.what you had exactly doneC.what is the matter D.when we would begin our next meeting8.I missed the history class. Could you tell me ________ A.what did you talk about B.what you talked aboutC.what do you talk about D.what you talk about9.—What did Alice say to you just now, Mike —She asked ________.A.if I could go to the movie with her this eveningB.where I go todayC.who did I go shopping with yesterdayD.when my brother will come back10.The teacher informed us that the moon ________ around the earth.A.moved B.moves C.will move D.is moving11.Our teacher told us that light ________ much faster than sound.A.traveled B.travel C.travels D.is travelling12.Can you tell me ________ A.where is your new friend fromB.where your new friend is fromC.where your new friend come fromD.where does your new friend come from13.He asked me ________.A.how did I get to Hubei MuseumB.why I liked hot dry noodles so muchC.how many bridges are there in WuhanD.what will I study in Wuhan University14.—Could you tell me ________ —Sure. It’s on Main Street.A.where is the post office B.where the post office isC.where was the post office D.where the post office was15.—________ bright room it is!—Yes, we all like it.A.What B.How C.What a D.How a16.—________ useful book it is!—Yes. It tells us how to learn English well.A.How B.What C.What an D.What a17.Superman can also burn things with his eye. ________ special eyes he has!A.What a B.What C.How a D.How18.—Listen! Someone is playing ________ piano.—Wow! ________ beautiful music! I like it very much.A.a; What B.the; How C.the; What D./; How19.— ________ Luoma Lake looks in the evening! —I quite agree with you.What a beautiful B.How a beautifulC.What beautiful D.How beautiful20.—It is said in a few years’ time, the food you ordered will be sent to you by drones.—________ fast China’s science and technology are developing these days!A.How B.What C.What a D.What an21.The trip that you took with Bob sounds really ____ to me. _____ I wish to go!A.exciting, What B.excited, What C.exciting, How D.excited, How22.—We haven’t seen each other since the war broke out.—Yes. ________ time flies! We’ve changed a lot.A.What B.How a C.How D.What a二、单词拼写23.I want to buy a house with a big g so that I can plant vegetables and flowers there.24.W leaves the room last should close the door.25.A thief(小偷)broke into the shop and s many things last night.26.Our family made many l with some red paper last week for the coming Spring Festival.27.I don’t know w I can achieve my dream or not, but I will never give it up.28.Yuan Longping is a great scientist. We all a him.29.We usually celebrate the Spring Festival with our r .30.Do you like ice cream for d 31.Guo Lanying is famous for f music.32.Don’t talk to s on your way home.33.After a long day, Tom (lie) down on the bed and went to sleep.34.Don’t talk with the (strange).35.In the story of Chang’e, Pang Meng wanted (steal) the medicine.36.I plan (send) a gift to my father tomorrow for Father’s Day.37.Mary wonders if there (be) a party at her house next Sunday.38.Before the guests came, we were busy (lay) out the food and fruits on the table.39. (who) wants to come into the room must answer a question first.40.The boy asked his father if the earth (move) around the sun in surprise.41.How (quick) the boy is writing!42.Chinese people believe that the new year is a time for (wash) away bad things.三、完形填空Have you heard of tomato festival During the festival, there are all kinds of activities, but the most 43 part is the tomato fight. It takes place at the end of the long celebration.44 the tomato fight, there are musical bands, street parties and so on. On the day of the fight, shopkeepers 45 their windows and doors to keep away from the tomato fight. At the same time, thousands of tourists and local people come to the town square together. Then large trucks full of tomatoes arrive. From the back of the large trucks, a great town band starts to 46 tomatoes at others. Then the crowds fight back, throwing the tomatoes at anything and anyone. Soon the streets are in the sea of red tomato juice.You must squash(压烂) the tomato before throwing it and you are allowed to throw 47 but tomatoes. It is usually over in less than half an hour. Many people are excited about the festival, while others are against it. They think it’s a waste of food. What do you think of it 43.A.boring B.famous C.successful D.traditional44.A.After B.Before C.In D.Between45.A.cover B.open C.break D.lay46.A.point B.sell C.shout D.throw47.A.everything B.something C.nothing D.anything四、阅读理解(一)After dinner, people sit together before the TV to watch the New Year’s program and chat with each other. About ten minutes before the ringing of the New Year’s bell, people let off the fireworks to welcome the New Year.A new beginning at the Spring FestivalSome of the customs are quite interesting. For example, at the Spring Festival, people will not sweep the floor, do the washing or take their rubbish out in order not to do away with their fortune. On New Year’s Eve, people like to stick the Chinese character “Happiness” upside down on doors or walls, because “upside down” in Chinese is a homophone of “coming” or “arriving”.Pasting couplets on the doorsThe custom of pasting couplets on the doors has a long history. In the ancient times, people hung short branches of peach trees on the doors or at the front gates to drive away the evil (邪恶的) things. Later they became peach wood boards with some Chinese characters written on them. With the invention of paper, on each of which was written a verse (韵文) line to welcome the new year to express wishes for happiness and good fortune.A family reunion dinnerAfter putting up couplets and pictures on the doors on New Year’s Eve, the last day of the twelfth month in the Chinese lunar calendar, each family gathers for a big meal called “family reunion dinner”. People will enjoy the food.The meal is more luxurious (奢华) than usual. Dishes such as chicken, fish and bean curd are necessary. In Chinese, their pronunciations sound like “Ji”, “Yu”, and “Doufu”, with the meanings of auspiciousness (吉祥), abundance (充裕) and richness. Sons and daughters working away from home come back to join their parents.48.What does the third paragraph mainly tell us about couplets A.The materials used to make them. B.Their history and function.C.The two ways to paste couplets.D.People’s wishes for the new year.49.What’s the underlined word “homophone” mean A.A word with the same meaning.B.A word with the same spelling.C.A word that has opposite meaning.D.A word with the same pronunciation.50.What’s the best title for the passage A.New Year’s Eve is an important traditionB.A family reunion dinner is special in ChinaC.Celebration activities on New Year’s EveD.The history of the Spring Festival(二)The bright weather on Saturday, June 15, brought the yellow sun, blue skies and green grass. But the strawberry brought the red.The ABPA(阿宾顿商业会)worked together for the last couple of months to bring back the strawberry festival. The members decided to hold this event with the welcoming of the Summer Solstice(夏至). The festival came alive again with the vendors(摊贩), games, and races all through the downtown.It started with a race for the kids. Children practised running before the race began, giving them many chances to come in first place. Dressed in a strawberry suit, Miss Strawberry, aka Gerrie Carey, president of Clarks, greeted the kids and took pictures with them. The kids got to draw strawberries on the pavements(人行道). They also played with water balloons.Local businessmen sold their strawberry treats, including strawberries and strawberry pies. Opened two months ago, Paul and Emily Bobensky, the owners of Lacka Lemonade, sold their fresh lemonade(柠檬味汽水). They normally go to the Farmer Markets. It was the first time they had appeared at the strawberry festival.Even though it's a strawberry festival, there was a pie-eating contest including blueberry pies. People gathered around and cheered as five men raced to finish pies without using their hands.The ABPA helped with the payment of the parking for the day. The Tea Shop raised money for St. Jude's Hospital. Everyone was happy and enjoyed the Strawberry Festival. It turned out to be a great success.51.How long did they prepare for the Festival A.For several days. B.For several months.C.For couple of weeks. D.For couple of years.52.What does the underlined word "gathered" in Paragraph 5 mean A.Set up. B.Got back. C.Got together. D.Got through.53.What's the people's attitude(态度)to the event A.Hate. B.Serious. C.Active. D.Curious.54.What would be the best structure of the passage A.B.C. D.参考答案题号 1 2 3 4 5 6 7 8 9 10答案 C B B A A B C B A B题号 11 12 13 14 15 16 17 18 19 20答案 C B B B C D B C D A题号 21 22 43 44 45 46 47 48 49 50答案 C C B B A D C B D C题号 51 52 53 54答案 B C C D1.C【详解】句意:——你知道在中国红色代表好运吗?——当然。考查宾语从句。how如何;where在哪里;that那,可引导陈述语气的宾语从句;what什么。根据“Do you know...red stands for good luck in China”可知,设空处引导宾语从句,且从句为一个成分完整的陈述句,因此此处用that引导宾语从句。故选C。2.B【详解】句意:里奥没有告诉我们他是否会参加会议,如果他决定来,我相信他会提前打电话。考查if引导的宾语从句和条件状语从句。根据分析句子可知,第一句是if引导的宾语从句,时态为:主过从过;第二句是if引导的状语从句,时态为“主将从现”。故选B。3.B【详解】句意:——这个项目对你的表弟来说太难了。——是的,我想知道他是否能独自完成。考查宾语从句。根据“I am wondering...”可知,空处填入的是宾语从句,为陈述语序,C、D都是疑问语序,可排除;“想知道的事情”是不确定的,应用whether来引导宾语从句,表示“是否”。故选B。4.A【详解】句意:——吉姆,新学期今天开始了。我想知道我们的化学老师是什么样的人。——我不太确定。但我听说是一位经验丰富的老师。考查宾语从句。根据“I wonder”可知,此处应是宾语从句,应用陈述句语序,排除B、D选项;根据“But I heard that it is an experienced teacher.”可知,此处应询问老师的外貌或者性格,A选项符合。故选A。5.A【详解】句意:——你能告诉我谁写的这个故事吗?——可以。这是美国作家欧内斯特·海明威写的。考查宾语从句。who wrote the story谁写的这个故事;when the story happened这个故事什么时间发生的;where the writer is from作者来自哪里;why people like the story为什么人们喜欢这个故事。根据“The American writer Ernest Hemingway wrote it.”可知,此处询问故事是谁写的,故选A。6.B【详解】句意:——你能告诉我超市在哪里吗?——它在邮局旁边。考查宾语从句。根据“Could you tell me... ”可知,空处是宾语从句;结合答语“It’s next to the post office.”可知,问句提问位置,所以应用where引导此宾语从句,且宾语从句应用一般现在时。故选B。7.C【详解】句意:你能告诉我怎么了吗?考查宾语从句。why were you in such a hurry你当时为什么这么着急;what you had exactly done你到底做了些什么;what is the matter怎么了;when we would begin our next meeting我们下次开会什么时候开始。宾语从句要用陈述语序,排除A选项,本句主句中的Could表示客气礼貌地提问,并不是过去式,所以主句的时态是一般现在时。当主句是一般现在时的时候,遵循“主现从不限”,B、D选项是主句为一般过去时情况下的选择。故选C。8.B【详解】句意:我错过了历史课。你能告诉我你们讲了些什么吗?考查宾语从句。根据“Could you tell me”可知,该句为宾语从句,使用陈述语气,排除选项AC;结合“I missed the history class.”可知,历史课是过去发生的,因此询问的内容也应该是过去的事情,时态需保持一致。故选B。9.A【详解】句意:——Mike,Alice刚刚和你说什么了?——她问我今晚是否能和她去看电影。考查宾语从句语序及动词时态。分析句子可知,这是一个宾语从句,宾语从句采用陈述语序,故排除C项;由问句可知,时态为一般过去时,故排除B、D项。故选A。10.B【详解】句意:老师告诉我们,月亮围绕着地球运转。考查时态。根据“the moon ... around the earth”和常识可知,月亮围绕着地球运转是客观事实和真理,用一般现在时。故选B。11.C【详解】句意:老师告诉我们光比声音传播得快得多。考查一般现在时的用法。题干描述的是客观事实(光速始终快于声速),需用一般现在时;主语为light,动词要三单。故选C。12.B【详解】句意:你能告诉我你的新朋友来自哪里吗?考查宾语从句。根据“Can you tell me ... ”可知,此句是宾语从句,宾语从句应用陈述语序,排除A和D;主语“your new friend”是第三人称单数,谓语动词应用三单形式is/comes,排除C。故选B。13.B【详解】句意:他问我为什么如此喜欢热干面。考查宾语从句。how did I get to Hubei Museum我怎样到达湖北博物馆,疑问语序;why I liked hot dry noodles so much我为什么如此喜欢热干面,陈述语序;how many bridges are there in Wuhan在武汉有多少座桥,疑问语序;what will I study in Wuhan University我将在武汉大学学习什么,疑问语序。根据句子结构可知,该空是宾语从句,从句中应用陈述语序,排除A、C和D。故选B。14.B【详解】句意:——你能告诉我邮局在哪里吗?——当然。它在主街。考查宾语从句的时态和语序。根据“Could you tell me”可知此处为宾语从句,语序为陈述句语序,而could表委婉语气,所以主句的时态为一般现在时,根据“主现从不限”的原则和语境可知此处时态为一般现在时,故选B。15.C【详解】句意:——多么明亮的房间啊!——是的,我们都很喜欢。考查感叹句。分析句子结构可知,此句为感叹句。中心词为可数名词单数的“room”,符合“What+a/an+形容词+可数名词单数+主语+谓语!”结构的感叹句。故选C。16.D【详解】句意:——多么有用的一本书啊!——是的,它告诉我们如何学好英语。考查感叹句结构。根据“useful book it is!”可知,该句中心词是可数名词“book”,符合的感叹句结构为“What+a/an+形容词+名词+主谓”,由于“useful”是以辅音音素开头的单词,应选用冠词“a”。故选D。17.B【详解】句意:超人还能用眼睛燃烧物体。他的眼睛多么特别啊!考查感叹句。根据“...special eyes he has!”可知,中心词是名词eyes,且为复数形式,应用what引导感叹句,句式为“what+形容词+可数名词复数+主谓”。故选B。18.C【详解】句意:——听!有人正在弹钢琴。——哇!多么动听的音乐啊!我非常喜欢。考查冠词和感叹句。play the piano“弹钢琴”,乐器前通常用定冠词the,故排除选项A和D。根据“beautiful music!”可知,此处为感叹句,中心词为名词,故此处应用“what+形容词+名词+(主谓)”的结构。故选C。19.D【详解】句意:——傍晚的骆马湖多美啊!——我非常同意你的观点。考查感叹句。looks为系动词,后应接形容词beautiful作表语,为中心词,应用how引导感叹句,结构为“ How+形容词+主语+谓语!”。故选D。20.A【详解】句意:——据说几年后,你点的食物将由无人机送给你。——如今中国的科学技术发展得多快啊!考查感叹句。本句是感叹句,强调的中心词是副词fast,符合结构:How+副词+主语+谓语。故选A。21.C【详解】句意:你和Bob一起的旅行听起来真令人兴奋。我多想去啊!考查形容词辨析及感叹句。exciting令人兴奋的,形容词物;excited感到兴奋的,形容人。第一空修饰“trip”用exciting;根据“...I wish to go!”可知此处满足how+主语+谓语的结构,用how引导感叹句,故选C。22.C【详解】句意:——战争爆发后,我们再也没有见过面。——是的。 时光飞逝! 我们改变了很多。考查感叹句。根据“…time flies!”可知,此处用how引导感叹句,结构为:how+主语+谓语。故选C。23.(g)arden【详解】句意:我想买一栋带大花园的房子,这样我就可以在那里种菜种花了。根据情境和“a house with a big”可知,是房子带有的一个地方;根据“I can plant vegetables and flowers there”可知,这个地方能种花和种菜,结合首字母“g”可知,应该使用“garden”,表示“花园”。故填(g)arden。24.(W)hoever【详解】句意:不论谁最后离开房间,都应该把门关上。根据“W… leaves the room last should close the door.”可知,此处表达的是不论是谁。“无论谁”whoever,放于句首,首字母需要大写。故填(W)hoever。25.(s)tole【详解】句意:昨晚一个小偷闯进商店偷了很多东西。根据“A thief broke into the shop”可知,小偷是去偷东西,and前后的时态保持一致,即一般过去时,steal表“偷”,过去式为stole。故填(s)tole。26.(l)anterns【详解】句意:上周我们家用红纸做了很多灯笼,为即将到来的春节做准备。根据“with some red paper last week for the coming Spring Festival.”结合首字母提示,可知这里表示“上周我们家用红纸做了很多灯笼”,名词lantern作宾语,符合题意,且被many修饰,用名词复数,故填(l)anterns。27.(w)hether【详解】句意:我不知道我是否能实现我的梦想,但我永远不会放弃。根据首字母提示和下文的“or not”可知,是说是否能实现我的梦想,whether“是否”符合句意,故填(w)hether。28.(a)dmire【详解】句意:袁隆平一个伟大的科学家。我们都很钦佩他。句子缺谓语动词,句子是一般现在时,主语是复数概念。根据“a great scientist”及首字母提示,可知表达钦佩,用动词原形“admire”。故填(a)dmire。29.(r)elatives【详解】句意:我们通常和亲戚一起庆祝春节。春节是家人团聚,走亲访友的日子。根据首字母提示可知,答案为(r)elatives。30.(d)essert【详解】句意:你喜欢冰激凌做甜点吗?根据ice cream和首字母,可知是甜点;故填(d)essert31.(f)olk【详解】句意:郭兰英因民族乐而著名。folk music民族音乐,固定表达;根据首字母提示和“Guo Lanying”可知,空格处应填“民族”。故填(f)olk。32.(s)trangers【详解】句意:不要在回家的路上和陌生人说话。根据“Don’t talk to”及首字母,可知,不要跟陌生人说话,stranger“陌生人”,此空应填复数名词表泛指,故填(s)trangers。33.lay【详解】句意:经过漫长的一天,汤姆躺在床上睡着了。根据“went to sleep”可知,时态为一般过去时,动词要用过去式;lie“平躺”,动词,其过去式为lay。故填lay。34.strangers【详解】句意:不要和陌生人说话。strange“陌生的”,形容词。talk with sb.“和某人交谈”,故此处应为stranger“陌生人”,可数名词,用其复数表泛指。故填strangers。35.to steal【详解】句意:在嫦娥的故事中,逄蒙想要偷药。want to do sth.“想要做某事”,故填to steal。36.to send【详解】句意:明天是父亲节,我打算送一份礼物给父亲。plan to do sth“计划做某事”,使用动词不定式作宾语,故填to send。37.will be/is going to be【详解】句意:玛丽想知道下星期天她家是否会举行聚会。本句为宾语从句,主句为一般现在时态,从句时态不受限制;根据“next Sunday”可知,从句使用一般将来时,结构是“will+动词原形”或“is going to+动词原形”。故填will be/is going to be 。38.laying【详解】句意:在客人们来之前,我们忙着在桌子上摆放食物和水果。lay out是一个固定短语,意为“摆放”,这句话中使用了句型be busy doing sth.忙于做某事,故这里填动名词形式laying。39.Whoever【详解】句意:任何想进房间的人都必须先回答一个问题。结合句意可知,此句是whoever引导的主语从句。意义相当于anyone who。40.moves【详解】句意:那个男孩惊讶地问他的父亲地球是否围绕太阳转。此处是客观事实,故用一般现在时,因为主语the earth是第三人称单数,故谓语用第三人称单数形式,故填moves。41.quickly【详解】句意:这孩子写得多快啊!根据句意可知,空处的词是修饰动词,应用副词;quick,快的,形容词,对应的副词是quickly。故填quickly。42.washing【详解】句意:中国人相信新年是冲走坏东西的时候。for是介词,后跟动名词作宾语,故填washing。43.B 44.B 45.A 46.D 47.C【导语】本文是一篇说明文,主要介绍西红柿节日及西红柿大战。43.句意:节日期间,有各种各样的庆祝活动,但是最出名的部分是西红柿大战。boring无聊的;famous著名的;successful成功的;traditional传统的。根据“all kinds of activities, but the most...”可知,此处介绍众多庆祝节日中最出名的是西红柿大战,且下文内容都在介绍西红柿大战。故选B。44.句意:在西红柿大战之前,有乐队、街头派对等等。After在……之后;Before在……之前;In在里面;Between在……之间。根据“It takes place at the end of the long celebration”可知,西红柿大战是最后的庆祝活动,其他庆祝活动在前面。故选B。45.句意:在西红柿大战这一天,店主们会盖好门窗,远离西红柿大战。cover覆盖;open打开;break打破;lay放置。根据下文“to keep away from the tomato fight”可知,为了避免西红柿大战殃及门窗,店主们会把店里的门窗遮盖好。故选A。46.句意:从大卡车的后面,城镇的一大帮人开始向其他人扔西红柿。point指向;sell卖;shout喊叫;throw扔。根据“tomatoes at others”以及“throwing the tomatoes at anything and anyone”可知,此处表达向其他人扔西红柿。故选D。47.句意:你必须在扔西红柿之前把它压烂,并且除了西红柿,不能扔其他任何东西。everything一切东西;something某些东西;nothing没有什么;anything任何东西。根据下文“but tomatoes”可知,西红柿大战时,只能扔西红柿,其他东西都不允许扔。故选C。48.B 49.D 50.C【导语】本文介绍了中国除夕的多种传统习俗等。此外,还详细阐述了贴春联的历史演变,再到纸张发明后书写韵文表达祝福,以及全家团聚享用年夜饭的习俗,展现了除夕丰富的文化内涵。48.主旨大意题。根据第三段中“The custom of pasting couplets on the doors has a long history.” “to drive away the evil things” 以及“express wishes for happiness and good fortune”可知,本段主要介绍对联的历史以及它的作用。故选B。49.词句猜测题。根据画线词所在句中“people like to stick the Chinese character ‘Happiness’ upside down on doors or walls”可知,人们喜欢把“福”字倒贴在门上以及墙上,倒贴福字即为“福倒了”。汉字“倒”与“到”是同音词。故选D。50.最佳标题题。文章依次介绍了除夕看电视、放烟花、贴福字、贴春联、吃年夜饭等习俗,围绕“除夕庆祝活动”展开。故选C。51.B 52.C 53.C 54.D【分析】【导语】文章主要讲述了 6 月 15 日阿宾顿商业会(ABPA)举办的草莓节。【详解】51.题意:他们为这个节日准备了多久?细节理解题。根据文中第二段首句 “The ABPA(阿宾顿商业会)worked together for the last couple of months to bring back the strawberry festival.”(阿宾顿商业会在过去几个月里共同努力,重新举办草莓节 。)可知,准备时间是几个月。“For several days.”(几天 )、“For couple of weeks.”(几周 )、“For couple of years.”(几年 )均与原文不符,所以正确答案为 B。52.题意:第五段中划线单词 “gathered” 是什么意思?词义猜测题。“gathered” 所在句 “People gathered around and cheered as five men raced to finish pies without using their hands.”(当五个人不使用手竞相吃完馅饼时,人们_____ 欢呼 。)结合语境,人们应该是 “聚集” 在周围,“Set up.”(建立;设立 )、“Got back.”(回来;恢复 )、“Got through.”(通过;完成 )都不符合此处表意,“Got together.”(聚集;集合 )与 “gathered” 意思相近,所以正确答案为 C。53.题意:人们对这个活动的态度是什么?细节理解题。从文中 “Children practised running...got to draw strawberries...played with water balloons.”(孩子们练习跑步…… 去画草莓…… 玩水气球 )、“Local businessmen sold their strawberry treats...”(当地商人售卖草莓美食…… )、“People gathered around and cheered...”(人们聚集起来欢呼…… )以及 “Everyone was happy and enjoyed the Strawberry Festival.”(每个人都很开心,享受草莓节 )等描述,能看出人们积极参与、享受活动,态度是积极的。“Hate.”(讨厌 )、“Serious.”(严肃的 ,侧重态度严谨,不符合此处人们愉悦参与的语境 )、“Curious.”(好奇的 ,文中体现的不只是好奇,更多是积极参与 )不符合,所以正确答案为 C。54.题意:这篇文章最好的结构是什么?篇章结构题。文章第一段是引入话题, 天气好, 草莓能带来一片红;第二段切入主题讲草莓节;第三、四、五段是分讲草莓节里的各项活动;第六段是对活动的总结。故全文是总一分一总的结构,所以正确答案为 D 展开更多...... 收起↑ 资源预览