自考365-自考学历培训

09年自考英语(一)课堂笔记(unit6)

2009-06-12 15:49    自考365论坛

报名

  Text A   Diamonds

  本课主要单词

  1.rare   adj. 稀有的,难得的

  These animals are so rare that I would do whatever I can to save them.〔这些动物很稀有,我会尽我所能去保护它们。〕

  On the rare occasions when the old lady had any post, the little boy downstairs would go and get it for her.〔老太太难得有信,只要有信总是楼下的小男孩帮她去拿。〕

  Snow is rare in this part of China.〔中国的这个地区难得下雪。〕

  It is very rare for him to say “Sorry” to any others.〔他难得会对任何人说“对不起”。〕

  Believe it or not, she is a rare beauty.〔信不信由你,她是一个百里挑一的美人。〕

  a rare word〔冷僻的词〕      rare metals〔稀有金属〕

  a rare disease(罕见的疾病)  a rare medicinal herb〔珍奇药草〕

  2.substance n. 物质;实质;大意;根据

  They were trying to remove harmful substances from the soil.〔他们正设法去除土壤里的有害物质。〕

  Ice, snow and water are the same substance in different forms.〔冰、雪、水是同一物质的三种不同形式。〕

  What was the point of going to a lecture with little substance?〔去听一个没有什么内容的讲座有什么意义呢?〕

  What he is saying in substance is that we should take effective measures to prevent pollution.〔他大体上说的是我们应该采取有效措施防止污染。〕

  There was no substance in his complaints.〔他的抱怨没有道理。〕

  3.slight adj. 轻微的;纤细的

  Mother said she had a slight headache.〔妈妈说她有点头疼。〕

  I didn't have the slightest idea about what had happened.〔我一点都不知道发生了什么事。〕

  His chances of winning the election are very slight.〔他在选举中获胜的可能性极小。〕

  He is too slight to play football.〔他太纤细,不能踢足球。〕

  4.extreme adj. 极端的,极度的;尽头的    n. 极端

  He died in extreme poverty.〔他在极度贫困中死去。〕

  You have to proceed your work with extreme caution.〔你得极其谨慎地继续你的工作。〕

  Extreme action will be taken if necessary.〔如有必要,我们将采取更严厉的行动。〕

  His hospitality was carried to an extreme.〔他好客得过分了。〕

  She found the book uninteresting to the extreme.〔她觉得那本书没意思透了。〕

  extreme joy/pain 〔极度的欢乐/痛苦〕 an extreme of sadness〔极度伤心〕

  go from one extreme to the other〔从一个极端走到另一个极端〕

  go to the other extreme 〔走到另一个极端〕

  in the extreme〔极度,非常〕

  extremes of poverty and wealth〔贫富的两极〕

  5.pressure n. 压力,压强

  The water pressure may need adjusting.〔水压可能需要调整。〕

  It was a pressure of five tons per square meter.〔每平方米的压力为五吨。〕

  Heavy study load and great expectation from parents may give children too much pressure.〔沉重的学习负担以及家长的过高期望可能会给孩子太大的压力。〕

  He was under constant pressure from his superiors.〔他的上司不断地给他压力。〕

  The doctor said this medicine could counteract his high blood pressure.〔医生说这种药能遏制他的高血压。〕

  6.liquid adj. 液体的,液态的;清澈的,明亮的    n. 液体

  The doctor put the patient on a liquid diet.〔医生规定那位病人吃流质。〕

  The little girl with large liquid eyes is my sister.〔那个长着一双水汪汪的大眼睛的小姑娘是我妹妹。〕

  She poured out a large quantity of yellowish liquid from a bottle.〔她从一个瓶子里倒出了许多黄色的液体。〕

  7.crack n. 裂缝    v. 破裂;打开

  She found a crack in one of the tea-cups.〔她发现一只茶杯上有裂缝。〕

  He heard the cracks of rifle fire in the distance.〔他听到了远处的步枪声。〕

  He asked his mother to crack some eggs for him.〔他请妈妈帮他敲碎几个鸡蛋。〕

  His face cracked with a broad smile. 〔他咧开嘴笑了。〕

  The phone cracked the room's quiet.〔电话铃声打破了房间的寂静。〕

  They were unable to crack a highly competitive sales market.〔他们无法打进竞争激烈的销售市场。〕

  8.crust n. 地壳;面包皮,外皮

  There are some brownish bread crusts on the dining table.〔餐桌上有一些棕色的面包皮。〕

  The white snow had a fine crust on the trees.〔树上覆盖着一层美丽的白雪。〕

  The continuous movements of the earth's crust may lead to earthquakes.〔地壳的不断运动引发了地震。〕

  It is very dangerous to walk on the thin crust of ice.〔在这样一层薄冰上行走是很危险的。〕

  9.crystal n. 水晶;晶粒    adj. 清澈透明的

  Mother gave her a necklace of crystals as a birthday present.〔妈妈给她一条水晶珠项链作为生日礼物。〕

  The old woman looked into the crystal ball for a while before telling my fortune.〔老妇人朝水晶球里看了一会,然后给我算命。〕

  I've made my point crystal clear that I would never agree to such a proposal.〔我已经表明了我的观点,绝不同意这个提议。〕

  10.popular adj. 流行的,大众的;普及的;受欢迎的

  Popular music is well liked by young people.〔流行音乐深受年轻人的喜爱。〕

  Swimming is a sport popular with people of all ages.〔游泳是老老少少都喜欢的体育运动。〕

  He has always been popular with / among boys in his community.〔他一直广受他那个社区的男孩子们的喜欢。〕

  This restaurant offers meals at popular prices.〔这家饭店供应价格大众化的饭菜。〕

  He is a good politician but he is not very popular among the people.〔他很会搞政治,但是不得民心。〕

  11.handful n. 一把,一小撮

  He told the doctor that his hair fell out in handfuls.(他对医生说他的头发一把一把地脱落。)

  The naughty boy gathered a handful of stones and began to throw them in the lake.〔那个调皮的男孩手里聚了一把石块,并把石块往湖里扔。〕

  He gave me nothing except for a handful of books.〔除了少量的几本书他什么也没给我。〕

  注意:一般来说,-ful是一个形容词后缀,加在名词后面可以构成形容词,比如: careful,helpful,useful,hopeful等等。而在handful这个单词中,-ful是一个名词后缀,加在某些名词的后面,表示 “充满…所需的量”,比如:roomful,basketful,mouthful,spoonful等等。

  12.formation n. 岩层;形成,构成

  Most diamonds are mined from rock formations inside the earth.〔大多数钻石都是从地下的岩层里开采出来的。〕

  The formation of good habits is very important for a child.〔好习惯的养成对孩子来说很重要。〕

  The teacher is explaining to the students the formation of the new word.〔老师正对学生们解释那个新词的构成。〕

  The peculiar formation of human brain drew the attention of researchers in many fields.〔人脑的奇特构造吸引了许多领域的研究人员。〕

  13.pipe n. 管子,导管;烟斗   v.用管道输送

  Tell the pipelayer that he has to be careful with the gas pipe.〔告诉管道安装工煤气管道要小心。〕

  The old man was sitting in the corner smoking a pipe.〔那个老人坐在角落里抽着烟斗。〕

  It won't be very troublesome to pipe water into the house.〔用管道把水送进屋里不会很麻烦。〕

  14.somewhat adv. 稍微,有点

  It is somewhat difficult for him to answer the question.(要他回答这个问题有点难。)

  I felt somewhat awkward when I couldn't remember his name.〔当我记不起他的名字时,我有点尴尬。〕

  The working conditions in this factory have somewhat improved.〔这家工厂的工作条件已有所改善。〕

  15.blast n. 疾风,强风;爆炸   v.炸,炸掉

  A blast of cold air sent a shiver all over his body.〔一股冷气使他浑身战栗。〕

  Furious blasts of thunder frightened everybody.〔一阵阵的霹雳炸雷吓坏了所有的人。〕

  The driver blasted the horn continuously.〔司机不停地按喇叭。〕

  Rock music blasted from the hall and the whole building seemed to be shaking.〔震天的摇滚乐从客厅传来,整座房子似乎都在摇动。〕

  They decided to blast through the mountains. 〔他们打算炸山开路。〕

  16.crush v. 压碎;镇压,压倒

  The machine can crush rocks into powder.〔那台机器能把石头碾成粉末。〕

  You must remember poverty should not crush one's spirit.〔你必须记住不应该因贫困而意志消沉。〕

  We didn't expect that they would crush us into this tiny room.〔我们没有料到他们会让我们挤在这个小房间里。〕

  Can you imagine that debts are crushing them?〔你能想像到债务正压得他们喘不过气来吗?〕

  17.destroy v. 破坏,毁灭;消灭

  Several buildings were destroyed by the bomb.〔几座建筑物都被炸弹炸毁了。〕

  He destroyed the letter as soon as he had read it.〔他一读完就把信毁了。〕

  I really don't want to destroy the friendship between us.〔我真不想毁坏我们之间的友谊。〕

  The loss of his wife and son finally destroyed him.〔失去妻儿更终击败了他。〕

  This poison can destroy rats.〔这种毒药可灭鼠。〕

  18.impressive adj.给人深刻印象的,感人的

  impression n. 印象

  impress v. 给…极深的印象

  She is trying to build an impressive international reputation.〔她正努力建立令人难忘的国际声誉。〕

  She said that all the places she had visited in China were impressive.〔她说她所游览过的中国的每一个地方都给她留下了深刻的印象。〕

  What are your impressions of Beijing?〔你对北京有何观感?〕

  I had the impression that he was a teacher.〔我记得他好像是个老师。〕

  What impressed me most were the great changes in this city.〔给我印象更深的是这座城市的巨大变化。〕

  She wants to impress her new boss with her diligence.(她想以勤奋加深老板对她的印象。)

  19.experience n 经验;经历    v. 经历,遭受

  experienced adj. 有经验的

  With no teaching experience my chances of getting the job are slight.〔我没有教学经验,得到这份工作的可能性很小。〕

  He is a man of rich experience.〔他是一个经验丰富的人。〕

  Everyone can learn a lot from his own experience.〔每一个人都从自己的经历中学到很多东西。〕

  His experience in the country could be used as material for his writing.〔他在农村的经历可以作为他的写作素材。〕

  He experienced a lot of hardships when he was abroad.〔他在国外时经历了许多艰辛。〕

  We need someone more experienced to help us.〔我们需要更有经验的人来帮助我们。〕

  He is more experienced than I am in planting trees.〔在植树方面他比我有经验。〕

  20.immediately adv. 即刻地;紧密地

  immediate adj. 立刻的;更接近的

  He said he had to go to the hospital immediately.〔他说他得立即去医院。〕

  She finished one cup of coffee and asked for another immediately.〔她喝完一杯咖啡马上又要了一杯。〕

  The post office is immediately next to the bank.〔邮局紧挨着银行。〕

  You have to give them an immediate reply.〔你得立刻答复他们。〕

  It is necessary that you get the support from your immediate superior.〔你必须得到顶头上司的支持。〕

  本课主要构词法

  affixation(词缀法)

  1.形容词后缀 -ful    beautiful,useful,

  2.形容词后缀 -ive    impressive

  3.形容词后缀 -y     greasy

  4.名词后缀 -ation    combination,formation

  5.名词后缀 -ure     pressure

  6.名词后缀 -y      discovery

  7.名词后缀 -er      traveler,miner

  8.名词后缀 -ful     handful

  9.副词后缀 -ly      finally,probably,immediately,carefully,

  10.副词后缀 -ward    upward

  课文简介

  本课主要介绍了钻石的特性、形成、分布以及开采方式。读了本课,你会了解钻石的形成与数百万年前的地壳运动有关;你也会了解深受上至达官贵人下至普通百姓喜爱的“恒久远”的钻石在刚开采出来时并不光彩照人。

  本课语言点

  1.They are the hardest substance found in nature.

  本句中found in nature是定语从句,修饰substance.定语从句中省略了that are.这种省略现象在定语从句中很常见,在前几个单元中,我们遇到过多次。请看下面的句子:

  1)There are many books (that) I'd like to read. (有很多书我想看。)

  2)He is a man (that) we all like and trust. (他是一个我们大家喜欢和信赖的人。)

  3)This is the most interesting film (that) I have ever seen. (这是我看过的更有意思的电影)

  先行词的前面有形容词更高级时,定语从句必须用that引导,而不用which.请看下面的句子:

  1)This is the most beautiful place (that) I have ever visited. (这是我游览过的更美丽的地方。)

  2)This is the most serious problem (that) we have ever met. (这是我们遇到过的更严重的问题。)

  3)They are the richest people (that are) living in this area. (他们是住在这一地区的更富有的人。)

  本句中的hardest意思为“坚硬的”“坚固的”,而不是“困难的”。请看下面的句子:

  1)This nut is as hard as rock. (这果子硬得像岩石。)

  2)He found it hard to make friends. (他觉得交朋友很困难。)

  2.That means a diamond can cut any other surface. And only another diamond can make a slight cut in a diamond.

  mean是一个很常见的词,本句中的意思是“意味着”。mean还有“意欲,企图,打算”的意思。请看下面的句子,注意mean在各句中的意思和用法:

  1)What do you mean by saying this to me? (你对我说这个是什么意思?)

  2)Friendship means everything to him. (友谊对他来说意味着一切。)

  3)The teacher's praise meant so much to the children. (老师的表扬对孩子们来说很重要。)

  4)I'm serious about this. I mean what I say. (我对此事是认真的,我说话算数。)

  5)I'm sorry, I didn’t mean to hurt you. (对不起,我无意伤害你。)

  6)They meant to finish the work ahead of time. (他们的打算是提前完成这项工作。)

  7)I meant to call you but I forgot. (我原打算给你打电话的,但我忘记了。)

  cut在前一个句子中做动词用,意思是“切割”,在后一个句子中做名词用,意思是“切面”。

  1)Who will cut the ribbon for the exhibition? (谁将为展览会剪彩?)

  2)I am going to have my hair cut today. (今天我要去理发。)

  3)The icy wind cut him to the bone. (他感到寒风刺骨。)

  4)The old man is cutting a figure in stone. (那位老人正在雕刻石像。)

  5)I had some cuts and bruises on my arms, but I'm ok. (我的臂上有些伤口和擦伤,但我没什么问题。)

  6)He made a smooth cut on the marble. (他在大理石上留下一个光滑的切面。)

  3.Diamonds are made from carbon.

  由……制成,可以用be made from和be made of两个词组来表达。但是be made from通常指制成品已看不出原材料是什么,而be made of可以看出该物品由什么材料制成的。如:

  1)Paper is made from some plants. (纸是由某些植物制成的。)

  2)This beer is made from grain. (这种啤酒是用粮食酿制的。)

  3)The houses were made of brick. (这些房屋是砖造的。)

  4)This toy is made of cotton. (这个玩具是布做的。)

  4.Scientists know that the combination of extreme heat and pressure changes carbon into diamonds.

  extreme在句中做形容词用,意思是“极度的”,如:

  1)Extreme cold can wake a hibernating animal. (极度的寒冷能使正在冬眠的动物苏醒。)

  2)They will have to endure extreme discomfort in winter. (冬天时,他们将不得不忍受极度的不适。)

  change…into意思是“把…转变为…”,如:

  1)Water changes into vapour when heated. (水加热后转变为蒸气。)

  2)Go to the bank and you can easily change these dollars into RMB. (你去银行就能很容易地把这些美元换成人民币。)

  5.Such heat and pressure exist only in the hot, liquid mass of molten rock deep inside the earth.

  请注意such与so之间的不同用法。such后面接名词,而so后面接形容词或副词。如:

  1)I don't believe he could make such a mistake. (我相信他不会犯这样的错误的。)

  2)How can you go out on such a rainy day? (在这样的雨天里,你怎么能出门?)

  3)He spoke so fast that I couldn't follow. (他说话太快,我听不懂。)

  4)I'm so glad you could come. (你能来我真高兴。)

  mass在本句中的意思是“(聚成一体的)团、块”,比如:

  1)a mass of hot air(一团热气)

  2)a mass of sand(一堆沙)

  3)Rain occurs when a mass of warm air is laden with water. (一团云聚集大量的水蒸气就形成了雨。)

  Mass也可以做形容词用,意思是“群众的”、“大量的”,如:

  1)a mass meeting (群众大会)

  2)mass education (大众教育)

  3)mass media (大众传媒)

  4)Mass production could very well cut the cost. (大规模生产可以降低成本。)

  6.It is thought that millions of years ago this liquid mass pushed upward through cracks in the earth's crust.

  It is thought that…是一个很常用的句型,类似的句型在英语中很多,比如:

  1)It is / was, has been…, reported that…

  2)It is / was, has been…, stated that…

  3)It is / was, has been…, pointed out that…

  4)It is / was, has been…, mentioned that…

  5)It is / was, has been…, believed that…

  7.A. There are only four areas where very many diamonds have been formed.

  B. The first known area was in India, where diamonds were found thousands of years ago.

  定语从句可分为限定性定语从句和非限定性定语从句。A句是限定性定语从句,B句是非限定性定语从句。A、B两句中都是用关系副词where来引导定语从句,修饰表示地点的名词。请看下面的句子,注意限定性定语从句一般不用逗号隔开:

  1)Is there a shop around where we can get some fruit? (附近有什么商店可以买到水果吗?)

  2)This is the place where we met yesterday. (这是我们昨天碰头的地方。)

  3)The small town, where he once worked, has turned to be a modern city. (他曾经工作过的那座小城,已经变成现代化的城市了。)

  8.In the 1600's…(十七世纪)

  In the 1720's…(十八世纪二十年代)

  In the 1800's…(十九世纪)

  请注意年代的表达方法,以上的年代也可以表达为in the 1600s; in the 1720s; in the 1800s.如果我们要表达“在十七世纪初(中、末)期”,则可以说in the early(mid, late) 1600's/1600s.

  9.Diamonds became very popular with the kings and queens of Europe.

  become / be popular with / among是一个常用词组,意思是“受…欢迎”,请看下面的句子:

  1)These Chinese handicrafts are very popular with foreign friends. (这些中国工艺品很受外国朋友的喜爱。)

  2)His novels are popular among young people. (他的小说很受年轻人的喜爱。)

  3)Classical music is popular among more and more people. (古典音乐受到越来越多的人的喜爱。)

  10.India's supply of diamonds was finally running out after 2,500 yeas of mining the stones.

  Supply在句子中做名词用,意思是“供应”。Supply常常可以做动词用,意思是“供给,提供”。请看下面的句子:

  1)Economic stability can be reached if demand and supply are in balance. (如果供求关系平衡的话,就能实现经济的稳定。)

  2)Many materials are in short supply. (许多材料供应不足。)

  3)The increasing world population will put a strain on food supply. (不断增长的世界人口将对粮食供应带来重负。)

  4)You have to supply him with an answer. (你得给他提供一个答案。)

  5)Most towns are supplied with tap-water and electricity. (大多数城镇都有自来水和电力供应。)

  run out是一个常用词组,意思是“用完,用尽”。请看例句:

  1)Time is running out. We have to hurry. (时间快到了,我们得快点。)

  2)My patience is running out. (我快要耐不住了。)

  3)His luck seemed to have run out. (他的好运似乎结束了。)

  我们也可以用run out来表达类似的意思,但run out of的主语应该是“某人”。如:

  1)They have run out of money, so they have to find a job. (他们钱用完了,所以得找一份工作。)

  2)I have run out of ink. (我的墨水用完了。)

  11.People would pick up handfuls of gravel from the bottom of the streams and sort out the diamonds.

  -ful通常加在名词后面,构成形容词,如care-careful,help-helpful.而本句中的handful是一个名词,意思是“一把”,在单词部分,我们已经提到过,英语中有不少这样的词,如:

  1)He gave me a basketful of beaches. (他给了我满满一篮子桃子。)

  2)She put a spoonful of salt in the soup. (她往汤里撒了满满一勺盐。)

  3)Tom is carrying an armful of books.(汤姆抱着一捆书。)

  sort out是一个常用词组,意思是“整理,分类”,如:

  1)Sort out those of bigger size and put them in a box. (把大点的整理出来,放在盒子里。)

  2)It took quite a while to sort out all our luggage. (把我们所有的行李整理好花了不少时间。)

  bottom在句子中做名词用,意思是“底部”。bottom还有“尽头、末端”的意思。请看例句:

  1)There is some deposit in the bottom of the teapot. (茶壶底部有些沉淀物。)

  2)At the bottom of the mountain, there is a beautiful village. (在山脚下有个美丽的村子。)

  3)I felt grateful to you from the bottom of my heart. (我衷心地感谢你。)

  4)Bottoms up. (干杯。)

  12.These diamonds were probably carried from where they were formed to India by great sheets of moving ice that covered parts of the earth 20,000 years ago.

  where they were formed是where引出的名词性从句,作介词from的宾语。请看下面的句子:

  1)He didn't say anything about where the accident took place. (他对事故在哪儿发生的只字未提。)

  2)She hasn't made up her mind as to where she should go for the holiday. (她还没有决定到哪儿去度假。)

  13.It flows over boards thickly coated with grease.

  在本句中的定语从句thickly coated with greases前面省略了which/that are.coat一般做名词用,意思是“外套”或“(动物的)皮毛”。在本句中coat作动词用,意思是“在…上涂(包)着”,如:

  1)These pills are coated with sugar. (这些药丸外面包着糖衣。)

  2)Don't jump on the bush piles, they are ice-coated and slippery. (不要在灌木堆上跳,上面盖着冰,很滑。)

  14.Since diamonds stick to grease, they are left behind by the rocks and mud which flow down the tables.

  Stick在本句中的意思是“粘住”。Stick to也可以表示“坚持,遵守”的意思。请看下面的句子:

  1)I'm sure father hasn’t read the book because several pages are stuck together. (我敢肯定父亲没有看过那本书,因为有几页还粘在一起。)

  2)It's important for nurses to stick to the rules. (对护士来说,遵守规定是很重要的。)

  3)Stick to your post and make sure everything is ok. (坚守你的岗位,确保一切正常。)

  leave behind在本句中的意思是“留下”,这个词组还可以表示“忘带;把…丢在后面”。例如:

  1)Take care not to leave anything behind. (小心别丢下任何东西。)

  2)Look forward to the bright future and leave all your worries and fears behind. (期盼光明的未来,把所有的担心和恐惧抛在身后。)

  15.Experienced diamond miners can tell a diamond immediately.

  句子中的tell意思为“判断;分辨;看出”。如:

  1)I cannot tell her from her twin sister. (我无法分辨出她和她的孪生妹妹。)

  2)Can you tell which is my school-bag? (你能分辨出哪一个是我的书包吗?)

  3)It is important for you to tell right from wrong. (分辨出正误很重要。)

  本课主要词组及语法要点

  A. 词组

  1.make a cut in sth.    2.change…into

  3.be made from      4.become popular with

  5.run out          6.pick up

  7.handfuls of       8.sort out

  9.carry from       10.be coated with

  11.stick to         12.leave behind

  13.tell…(from)      14.find out

  B. 语法要点

  1.被动语态

  2.定语从句

  3.状语从句

  4.主语从句

  Text B  The Difference between Plants and Animals

  短语表达

  1.difference between…and

  Will you please tell me the difference between a horse and a seahorse?

  I cannot hear any difference between the American pronunciation and the British pronunciation for this word.

  2.neither …nor

  He is not a person to rely on as he is neither honest nor sincere.

  I have neither seen him nor heard from him since we last met.

  3.look up

  Father didn't look up from his book when I entered the sitting room.

  The little boy didn't dare to look up at his teacher.

  4.a matter of

  Everybody would pay some attention to the contest as it is a matter of honor.

  Don't panic. This is a matter of record and there is nothing to worry about.

  5.throughout

  The products of this factory will be supplied to people throughout the country.

  He said that a person should be honest and upright throughout his life.

  6.be satisfied with

  Tom was fully aware of the consequence when his father saw his test paper.

  The teacher was satisfied with the students' performance.

  7.take place

  Great changes have taken place in China in the past 20 years.

  The accident took place when people were all fast asleep.

  8.lie in

  The importance of this book lies in its later influence.

  The root of all these events lay in history.

  9.be classed as

  He was classed as a genius.

  Some kinds of seaweed are animals but they used to be classed as plants.

  10.hold good

  This rule may hold good for you but not for me.

  His answer doesn't hold good for this specific question.

  11.live on

  Cows live on grass.

  The old man lives on the government pension.

  12.work wonders

  I don't think this medicine will work wonders.

  We didn't think he could pull through this time but he worked wonders again.

  13.take in

  Their club took in some new members last week.

  He took in his guest and offered him a cup of coffee.

  14.suck up

  The plants suck up a lot of water.

  He sucks all the information you gave him.

  15.take up

  He took up the newspaper and began to read.

  She took up English when she was only five.

  All the window seats had been taken up when I got on the bus.

12345678910111213141516171819202122232425
分享到:
小自考
相关资讯
更多课程推荐