八年级上册英语【完形填空】专练20篇(含答案)(一)It was the last lesson before 1 holidays. The students 2 very happy. Their English teacher was very happy, 3 .The teacher 4 played nice games with them. He sang some nice songs, and then he went to the blackboard and wrote “SMILES” 5 it.“This is one of the 6 words in English”,he said to the class. The 7 class laughed, and then one girl 8 and said,“Why is it one of the longest words in English?”The teacher said 9 for a while. Then he smiled and said,“Because there is a mile between the 10 letter and the last.”()1. A. a B. an C. the D. much()2.A.is B. are C. was D. were()3.A.too B. eight C. neither D. also()4. A. a little B. little C. any D. also()5.A.before B. on C. in D. in front of()6.A.long B. longer C. longest D. short()7.A.whole B. each C. all D. both()8. A. stand up B. sit downC. stood upD. lay down()9. A. something B. anythingC. nothingD. everything()10.A.one B. first C. two D. second(二)It was the last lesson before 1 holidays. The students 2 very happy. Their English teacher was very happy, 3 .The teacher 4 played nice games with them. He sang some nice songs, and then he went to the blackboard and wrote “SMILE S” 5 it. “This is one of the 6 words in English”, he said to the class. The 7 class laughed, and then one girl 8 and said, “Why is it one of the long est words in English?” The teacher said 9 for a while. Then he smiled and said, “Because there is a mile between the 10 letter and the last.”()1. A. a B. an C. the D. much()2.A.is B. are C. was D. were()3.A.too B. eight C. neither D. also()4. A. a little B. little C. any D. also()5.A.before B. on C. in D. in front of()6.A.long B. longer C. longest D. short()7.A.whole B. each C. all D. both()8. A. stand up B. sit down C. stood up D. lay down()9. A. something B. anythingC. nothingD. everything()10.A.one B. first C. two D. second(三)It was Sunday yesterday. Henry wasn’t __1_ home. He was on a __2_ to the zoo.An old man got on the bus. Henry stood up and __3__ to him, “Come and sit here, please.” He helped the old man __4_. “Thanks __5__, good boy,” the old man said. “You’re welcome,” said Henry.The bus went on. Thirty minutes later, it stopped __6_ the zoo. Henry got off the bus and said __7__ to the old man. The old man smiled(微笑) at him in a friendly way.Henry went into the zoo. __8__ of the people there are students. He _9_ a lot of animals and birds, and he also took many photos. He spent a happy weekend __10__ he helped others and had a good time in the zoo.( )1. A. in B. on C. at( )2. A. way B. zoo C. bus( )3. A. spoke B. said C. told( )4. A. go for B. get on C. sit down( )5. A. a little B. a lot C. a bit( )6. A. next B. through C. near( ) 7. A. hello B. goodbye C. yes( )8. A. Most B. Each C. Every( )9. A. found B. looked C. saw( )10. A. because B. but C. when(四)Since the 18th National Congress of the Communist Party (党的十八大),China has been asking to __1__ wasting food. It is said that the __2__ wasted in China every year could feed up to 200 million people.The Chinese are kind-hearted---this is well known.To__3__their respect to guests, they have formed the __4__ of offering much __5__ food than needed .If all the food has been 6 at the end of the dinner, the host could feel __7__ for being shame. But now ,many people will have a new habit---DaBao. It __8__ that at the end of a dinner, the food left will be packed and __9__ back home. We all know this is a __10__ habit.So boys and girls, from mow on, let’s change our habit. When we have 11 in restaurants, don’t order12 food. And try to eat up all the food. Please give up the snacks 13 meals. Encourage your classmates and parents to join us. 14 you find somebody is throwing away food, just stop them. Because the government (政府)has asked 15 of us to stop wasting food .we should pay much attention to it.( )1.A. begin B. form C. stop D. prepare( )2.A.money B. food C. rice D. water( )3.A.get B. prove C. give D. show( )4.A.way B. idea C. habit D. suggestion( )5.A.more B. less C. better D. delicious( )6.A.eaten up B. taken upC. put upD. picked up( )7.A.shy B. happy C. sad D. generous( )8.A.says B. calls C. means D. makes( )9.A.taken B. wasted C. thrown D. given( )10.A.wonderful B. different C. same D. easy( )11.A. dinners B. parties C. meetings D. sports( )12.A.too little B. too much C. too delicious D. too hot( )13.A.in B. with C. among D. between( )14.A. If B. though C. since D. unless( )15.A. some B. none C. one D. every one(五)Years ago, my friends and I went to the Caribbean. We stayed at the Winding Bay Hotel first. The owner of the hotel, Mr Emeritus,, was ___1___ and always ready to help others. ____2__ days lat er, we were planning to 3 for four days at the Cable Beach Hotel at another place. Mr Emeritus told us that he knew the owner of it. He gave us his 4 and told us give it to front desk when we got there. We thought that we might receive a fruit basket or something like that , because the 5 knew each other.6 we arrived at the Cable Beach Hotel, I gave the card to the front desk. The man 7__ us up to our room. We 8 our time at the hotel. When we would leave, the man told us we only needed to 9 one phone call. I toldhim that he made a mistake, 10 he told us that Mr Emeritus had paid for everything else. We were so 11After we returned home, we sent a 12 to Mr Emeritus and thanked him for making our 13 memorable(难忘的). For years, we kept 14 Christmas cards to him, and he sent them to us, too! 15 honest owner Mr Emeritus is !()1. A. humorous B. niceC. handsomeD. honest()2. A. A few B. Few C. Little D. A little()3. A. stay B. live C. work D. study()4. A. money B. number C. card D. address()5. A. hosts B. hotels C. waiters D. owners()6. A. When B. Before C. If D. Until()7. A. told B. took C. caught D. carried()8. A. had B. spent C. took D. enjoyed()9. A. look for B. wait forC.pay forD.ask for()10. A. and B. or C. so D. but()11. A. frightened B. generousC. popularD. surprised()12. A. note B. letter C. e-mail D. money()13. A. taste B. advice C. trip D. practice()14. A. buying B. sendingC. makingD. hoping()15. A. What an B. WhatC. How aD. How(六)Mike was a little boy. One day Mike went with his father to 1 his grandparents by train. 2 the train, Mike put his head out of the window. His father said, “Mike, be 3 ! Don’t put your head out of the window!” But Mike didn’t 4 his father. His father could do 5 .Then Mike’s father wanted to 6 a joke on his son. He took Mike’s cap quietly, hid (藏) it 7 his back and said, “You see, your cap has flown(飞) 8 .” Mike touched his head and it was really gone. The boy looked 9 and then he began to cry. He wanted to get his cap back.“Don’t worry, son.” said his father, “I have a strange 10 to get your cap back.” “11 can you get it back?” asked Mike in surprise.His father said, “Close your eyes and whistle(吹口哨)once, and maybe your cap will come back.” Mike came 12 to the window, closed his eyes and whistled. Just at that 13 , his father q uickly put the cap on the son’s head.“Oh! It is 14 !” Mike laughed. He was pleased, then he quickly took his father’s cap and 15 it out of the window. “Now it is your turn to whistle, Dad!” he said happily.1.A. look B. see C. watch D. notice2.A. At B. Of C. To D. In3.A. quick B. happy C. careful D. quiet4.A. answer B. look at C. hear D. listen to5.A. nothing B. anything C. some D. any6.A. do B. work C. play D. take7.A. before B. behind C. after D. at8.A. away B. high C. around D. out9.A. worried B. glad C. happy D. nervous10.A. road B. path C. way D. street11.A. Why B. How C. What D. Where12.A.on B. in C. up D. out13. A. while B. second C. minute D. moment14. A. terrible B. wonderfulC. badD. lovely15. A. threw B. placed C. brought D. got(七)Do you like going to the movies? Most of the1in high schools like movies very much. Last Sunday I went to a school and asked some students 2their favorite movies.3of their answers were really interesting. Here are their likes and 4 :Jim, a5boy, likes watching thrillers(恐怖片)because they are scary6 exciting. His class mate, Kate can’t stand documentaries(纪录片). She told me they were7parents. But she really likes comedies because they are funny. Jack is a big boy. He said he8mind documentaries. But he doesn’t like comedies9they are boring! And the coolest movies are action movies. Everyone10them very much!1.A.teachers B. students C. parents D. peop le2.A.about B. of C. at D. from3. A. Any B. Some C. Lot D. Much4. A. dislike B. dislikes C. hobbies D. enjoyments5. A.13-year-old B.13-years-oldC.11 year-oldD.11-years-old6. A. also B. too C. but D. and7. A. for B. with C. to D. of8. A. can’t B. didn’t C. doesn’t D. couldn’t9. A. so B. why C. because D. before10. A. enjoy B. enjoys C. watch D. watches(八)It was Monday. Mrs. Smith's dog was 1 , but there was no meat in the house. Thinking that there was no other 2 , Mrs. Smith took a piece of paper, and wrote the following words on it:" 3 my dog 0.1kg of meat." 4 she gave the paper to her dog and said, " Take this to the bu tcher, and he's going to give you 5 lunch today. "Taking the piece of paper in its 6 , the dog ran to the butcher's shop. 7 gave the paper to the butcher. The butcher read it carefully , and recognized (辨认) that it was 8 Mrs. Smith's handwriting(笔迹). So he did as Mrs. Smith told him. The dog was very 9 , and ate the meat up at once. At midday, the dog came to the shop for the10 time. It gave the butcher a piece of paper again. 11 reading it, he gave it 0.1kg of meat again.The next day, the dog came again just at midday. And as usual, it brought a piece of paper in the mouth. This time, the butcher did not 12 the paper, and gave the dog its meat, for he 13 the dog as one of his customers(顾客). But, the dog came again at 4:00 p.m. And the same thing happened once again. To the butcher's surprise, it 14 for the third time at 6:00 p.m. "This is a small dog. 15 does Mrs. Smith give it so much meat to eat today?" Looking at the piece of paper, he found that the re were no words there.()1. A. hungry B. thirsty C. hot D. ill()2. A. food B. time C. way D. person()3. A. Take B. Bring C. Get D. Give()4. A. If B. Then C. But D. Before()5. A. your B. our C. his D. my()6. A. mouth B. bag C. clothes D. hand()7. A. Mrs. Smith B. The man C. It D. They()8. A. so B. really C. look D. much()9. A. sad B. active C. funny D. happy()10. A. first B. second C .third D. fourth()11. A. When B. After C. Until D. though()12. A. make B. watch C. take D. look at()13. A. stayed B. planned C. thought D. made()14.A.came B. went C. took D. looked()15.A. What B. When C. Where D. Why(九)Everyone in our school loves sports. Every morning after we get up, we do morning exercises. After 1 second class, we do exercise again. We only have 2 class twice a week, but we do sports at five every afternoon. The most popular sport is basketball. The 3 enjoy playing it and many of the girls like it, too. 4 popular sport is football and in every class there _5 a lot of football fans. And We often play 6 in the gym. We have school teams of basketball, football and volleyball. Our teams often 7 friendship(友谊) games with teams from other schools. When there is a game, 8 of us go to watch it and cheer our side 9 .Besides (除了……以外) ball games, some of us like track and field events(田径项目), and we often 10 running, jumping and throwing . Every term(学期) we have tests in these events and once a year we hold a sports meeting.Sports help us keep healthy and happy.( )1.A. a B. the C. an( )2. A. English B. Chinese C. P.E( )3. A. teachers B. boys C. students( )4. A. Some other B. The other C. Another( )5. A. are B. is C. were( )6. A. basketball B. football C. volleyball( )7. A. see B. have C. watch( )8. A. much B. many C. few( )9. A. at B. on C. in( )10. A. learn B. study C. practice(十)My name is Steve. I move into this house __1_____ weeks ago, and I really enjoy__2_____here.There’s only one bedroom, and at the moment my sister is staying with me because she is __3____ a job.I work in a big company(公司).It’s hard__4____, and the hours are really long , but I like it. And it pays well. I don’t really __5____worried about my work.The only thing I don’t like about this house is one of the neighbo rs, Mrs.Snell, I think her name is. She’s really strange.She never speaks to___6____, I always says hello to her, and “ Are you all right?’ and what a lovely day today!”,but she never says a word.____7___she doesn’t like young people.My sister and I had a party a few days ago. It really wasn’t very noisy(吵闹). About ten of us were here____8___11.00pm and then we went out to dance. When I saw Mrs. Snell the next day, I said I hoped there wasn’t __9_____niose(噪音)for her, but as she didn’t saying anything. Funny lady.This evening my sister and I are going to visit a friend of ours who is in hospital, and then we ___10____out for a Chinese meal.1.A. few B. a few C.little D. a little2.A. live B. lives C. l iving D. to live3.A. seeing B. looking atC. findingD. looking for4.A. work B. job C. something D. matter5.A. want B. feel C. think D. have6.A. someone B. anyoneC. no oneD. everyone7.A. Maybe B. May be C. Like D. For8.A. After B. until C. when D. before9.A. too much B. much tooC. manyD. much10.A. go B. went C. are going D. aren’t going(十一)WhenMr Smith retired(退休), he bought a small 1 ina village near the sea. He2 itand hoped to live a quiet life in this house.Butto his great surprise, many tourists came to see his house in summer holidays,for it was the most 3 building in the village. From morning tonight there were 4 outside the house. They kept looking intothe rooms throughthe windows and 5 of them even went into MrSmith’s garden. This was too much for Mr Smith. He decided to ask the visitorsto 6 . So he put a notice on the window. The notice said, “If you want7 your curiosity(好奇心),come in and look round. Price: twentydollars.” Mr Smith was sure that the visitors would 8 coming,but he was wrong. More and more visitors came and Mr Smith had to 9 every day showing them around his house.“Icame here to 10 not to work as a guide(导游),”he said angrily. In the end, he sold the house and moved away.()1.A.garden B. shop C. house D. school()2. A.liked B. hated C.sold D. built()3. A.big B. interesting C. small D.clean()4. A.children B. students C. parents D. tourists()5. A.no B. none C. many D.much()6. e B. leave C. stay D. play()7. A.to satisfyB. satisfy C. to satisfying D. satisfying ()8. A.go on B. stop C. continue D. not()9. A.take B. cost C. spend D.pay()10.A. play B. work C. watch D. retire(十二)One day, a boyhad a fight with one of his classmates. Then he went to his 31 and told him his story angrily. “He is reallybad,” the boy said, “and I 32 him.”The grandfathersaid, “33 metell you a story. When I was a boy, I too, sometimes hated others for what theydid. …..”As the boy 34 carefully, the grandfather went on, “There arealways two tigers inside my heart. One is 35 and kind. He gets on well 36 everything around him. But 37 is bad and unfriendly. Even the smallest thingwill make him angry. He fights with everyone all the time, and for no reas on.He can’t think carefully 38 he always hates others. It is difficultto live with these two tigers inside my heart. They both try to control(控制) me. ”The boy lookedinto his grandfather’s 39 and asked, “40 tiger always controls you, Grandfather?”The old man saidslowly and seriously, “The one that I feed. I always feed the good and kindtiger, so I never hate others and seldom(很少) getangry now. ”()31. A. mother B.father C. teacher D. grandfather ()32. A. love B.hate C. know D. enjoy()33. A. Make B.Help C. Let D. Ask()34. A. saw B.felt C. talked D. listened()35. A. good B.bad C. lazy D. quiet()36. A. at B.on C. with D. about ()37. A. other B.others C.another D. the other()38. A. because B.though C.before D. but ()39. A. eyes B.ears C. nose D. mouth ()40. A. Who B.Which C. Where D. When(十三)One day a mother rat and her babies were outin an open field. They were playing and having a good time when suddenly ahungry cat came on the scene! It hid 41__ a big tree and then looked forwardthrough the tall grass 42__ itcould almost hear them talk. Before the mother rat and her babies knew 43 had happened, the cat jumped from its hidingplace and started to run 44_them.The mother cat and her babies all fled atonce. They hurried towards 45 home, which was under a pile of large stones.But the baby rats were so scared (害怕) that they could not run very 46_ . Closer and closer the cat came. Inno time the cat would be upon them. What was to be done?The mother rat stopped running, 47 round and faced the cat, shouting,"Bow Wow! BowWow! "just like 48 angry dog. The cat was so surprised andfrightened that it ran away.The mother rat turned to the babies,"Now you see 49 important it is to learn __50 second language!"()41 A. on B.between C. by D. behind()42. A. before B. when C. until D. while()43. A. where B. what C. which D. when()44. A. over B. through C. after D. against()45. A. to B. for C. its D. their()46. A. freely B. hardly C. soon D. quickly()47. A. turned B. walked C. jumped D. ran()48. A. a B. an C. their D. that()49. A. so B. why C. what D. how()50. A. out B. the C. a D. an(十四)London isa beautiful city. It is very large. The Thames Riverruns 42 the city from west to east. So the city has 43 parts: the South and the North. In the North,there are important buildings, shops, big parks and interesting places.Theweather in Londonis good. In winter it is not very cold and in summer it is not very hot 44 the city is near the sea. People say 45 Londonis a foggy city and it often rains. It is true.Last year, when I 46 in London I met one of the 47 fogs in years. You could hardly see your handin front of your face. Cars and buses moved along with their lights on. Whenevening came, the weather got 48 worse. The fog was as thick as milk. 49 the buses and cars stopped. I had 50 an important meeting on the other side of thetown, but it was impossible to find a car. I had to get there 51 .()1. A.about B. through C. in D. along()2. A.four B. six C. five D. two()3. A.because B. so C. but D. or()4. A.what B. where C. that D. which ()5. A.were B. am C. be D. was()6. A.big B. bigger C. bigest D. biggest ()7. A. wore B. even C. very D. some ()8. A.All B. Each C. Every D. None()9. A. tojoin B. to go to C. take part in D.join in ()10. A. by car B. by bus C.on foot D. on the foot(十五)Paulgot 26 the bus to go to the town. It was very crowded and he had tostand for about five 27 . Thensome of the people got 28 . Paul sat down next 29 a fat woman. She 30 several shopping bags and Paul didn’t havemuch place 31 the seat. He wasn’t uncomfort able. 32 last the bus got to the town. All the peoplestarted to get off. Paul was very polite, so he stood 33 to let the fat woman get off before him. She said,” 34 .” Then she tried to get 35 the seat with all her bags. But shecouldn’t move. She was too fat and her bags were too heavy.( ) 26.A. off B. on C. down D. up( )27. A.minutes B. days C. weeks D. years( )28. A.off B. up C. on D. down( )29. A. in B. at C. near D. to( )30. A.carries B. buys C. had D. has( )31. A. in B. at C. on D. upon( )32. A. In B. At C. On D.Up( )33. A.down B. under C. up D. at( )34. A. Goaway B. Go at once C. Look out D. Thank you( )35. A. down to B. off C. on D. out of(十六)Mark lived in a village far away. One day he became very ill and everyone thought he would 1 soon. They sent for a doctor. Two days 2 the doctor came and looked over the sick man. 3 asked for a pen and some paper to write down the name of the medicine. But there was no pen 4 paper in the village, because no one could write.The doctor 5 up a piece of burnt wood from the fire and wrote the name of the medicine on the 6 of the house. “ Get this medicine for him.” he said, “and he will soon get 7 .” Mark’s family and friends did not know 8 to do. They could not read the strange words. Then a young man 9 an idea. He took off the door of the house, put it on his carriage(马车) and drove to the nearest 10 . He bought the medicine there, and Mark was soon well again.( )1.A. wake B.cry C.moved D.die( )2.A. late ter C.ago D.before( )3A. The sick man B.Mark C.The doctor D.The farmer( )4.A.and B.or C.then D.also( )5.A.picked B.held C.made D.looked( )6.A.wall B.window C.ground D.door( )7.A.well B.worse C.bad D.good( )8.A.when B.what C.where D.whick( )9A.thought B.hit C.caught D.had( )!0. A.shop B.farm C.hospital D.village(十七)Peter and Mike were in 1 class.Peter was born in a 2 family.But Mike’s father was a businessman(商人)and got 3 money.When Peter got into trouble(困难)he always helped him.Peter liked to have sports.He was good at 4 .He ran 5 than any others in their class It was Sunday.Mike and Peter went to a forest to have a picnic.Mike took a lot of food there.It was a 6 ay.The birds were singing and there were all kinds of flowers.They ate and drank then went 7 in the river.They had a good time.Suddenly they heard a great noise.They found it was a tiger behind a big tree.They were both very 8 .Peter put on his shoes quickly and was going to run away.Mike stopped him and said:”It’s no use for us.The tiger runs 9 faster than us.Let’s find a way.”“It doesn’t matter.”said Peter.”I’m 1 0, I'll run faster than you.”1.A.same B.different C.difference D.the same2.A.rich B.happy C.poor D.bad3.A.many B.lot C.any D.much4.A.ran B.running C.run D.runs5.A.fast B.faster C.fastest D.best6.A.sun B.rain C.rained D.sunny7.A.fish B.to fishing C.fishing D.fished8.A.happy B.afraid C.sad D.exciting9.A.more B.much C.many D.1ittle10.A.afraid B.worried C.sure D.glad(十八)We were going to play a team from a country school .They didn’t come 1 the match nearly began .They looked 2 than we thought .The wore dirty T-shirts and blue jeans and looked like farm boys .We thought they 3 saw a basketball before .We felt that we didn’t 4 any practice to play with such a team .It was very late so they couldn’t have any time to practice .The match began ,one of our boys 5 the ball and he tried to give it to another one . But from out of nowhere a boy in a T-shirt 6 the ball and he quickly and beautifully got the ball into our basket and had two points .They 7 us .They had another two points in a minute .Soon it was all over .The country team 8 the match .Of course we knew that there was still another team 9 than any good team .But the important lesson we learn this time was : One can’t tell a man or a team by the 10 .()1、A. when B. so C. until D. at()2、A. stronger B. younger C. worse D. better()3、A. never B. often C. sometimes D. always()4、A. have B. make C. use D. need()5、A. got B. played C. took D .carried()6、A. caught B. changed C. held D. stopped()7、A. surprised B. frightened C. admired D. smiled()8、A. lost B. won C. got D. had()9、A. worse B. less C. better . D more()10、A. T-shirt B. appearance C. name D. points(十九)Mary has some friends. 1 Betty, Peter, Alice 2 Mike. Mary is the oldest 3 . Betty is thirteen years 4 . She is younger than Mary and older than Peter. Alice is nice and Mike is seven.Betty and Peter are 5 runners. But Peter runs faster. Mary and Betty like to 6 . Mary plays better than Betty. Alice sings 7 of them. Mary and Betty study in a middle school. Alice and Mike study in a primary school.They 8 work hard at school. But Betty works 9 . Her handwriting is good, 10 .( )1. A. They are B. It isC. There are D. We are( )2. A. but B. orC. them D. and( )3. A. in the five B . of fiveC. of the five D. for the five( )4. A. older B. oldC. oldest D. very old( )5. A. best B. betterC. well D. good( )6. A. play basketball B. play a basketballC. play the basketballD. play basketballs( )7. A. good B. betterC. best D. well( )8. A. six B. allC. four D. both( )9. A. hard B. harderC. very hard D. hardest( )10. A. too B. twoC. at D. also(二十)Perhaps you have heard _1 __about the Internet, but what is it?The Internet is many different networks around the world. A network is a group of computers put together. These networks joined together are called the Internet._2 that doesn't sound interesting. But 3 we've joined the Internet, there are 4 things we can do. We can have a lot of 5 on the World Web.(www). We can use the Internet instead of a library to 6 all kinds of information 7 our favorite sports or film stars and do shopping on the Internet. We can send message to other people 8 e-mail. I's much cheaper and quicker than 9 our friends or sending a letter.Thanks to the Internet, the world is becoming smaller and smaller. People can now work at home with a computer in front, getting and sending the information they need. They can buy or sell whatever they want by the Internet. But do you know 98% of the information is 10 English? So what will English be like tomorrow?1. A. a lot of B. a lot C. a few D. a little of2. A. May B. But C. And D. Maybe3. A. where B. when C. however D. although4. A. lots of B. a lot C. much D. few5. A. interesting B. friends C. interest D. funny6. A. find B. look for C. find out D. look after7. A. with B. for C. on D. about8. A. with B. by C. on D. for9. A. call B. called C. calls D. calling10. A. on B. with C. in D. for参考答案(一)1-5 CDADB 6-10 CACCB(二)1-5 BADBB 6-10 CACCB(三)1-5 CCBCB 6-10 CBACA(四)1-5 CBDCA 6-10 AACAA 11-15 ABDAD (五)BAACD ABDCD DBCBA(六)BDCDA CBAAC BCDBA(七)BDABBA DABCB(八) ACDBA ACBDB BDCAD(九)B C B C A C B B B C(十)B C D A B B A B A C(十一) CABDC BABCD(十二) DBCDA CDAAB(十三) DCBCD DABDC(十四) BDACD DBABC(十五) BAADC CBCDD(十六) DBCBADABDC(十七)DCDBBDCBBC(十八)CCADA AABCB(十九)ADCBD ACBDA(二十)BD BAC AD B DC。