Who Owns the Moon?
Within the next ten years, the U. S., China, Israel, and a crowd of private companies plan to set up camp on the moon. So if and when they plant a flag, does that give them property rights?
A NASA working group hosted a discussion this week to ask: Who owns the moon? The answer, of course, is no use. The Outer Space Treaty, the international signed by more than 100 countries, states that the moon and other celestial bodies (天體) are the province of all mankind. No doubt that would annoy all of the people throughout the ages, like monks from the Middle Ages, who have tried to claim the moon was theirs.
But ownership is different from property rights. People who rent apartments, for example, don’t own where they live, but they still hold rights. So with all of the upcoming missions (派遣團) to visit the moon and beyond, space industry thought leaders are seriously asking themselves how to deal with a potential land rush.
“ This is a very relevant discussion right now. We’ve got this wave of new lunar missions from around the world,” said William Marshall, a scientist in the small-spacecraft office at NASA, but who spoke this week at an event hosted by NASA’s Co Lab, a collaborative(協(xié)力完成的) public-private working group. He was speaking from his personal interest and not on behalf of the agency.
To be sure, the United States aims to send astronauts back to the moon by as early as 2015, in a mission that would include a long-term settlement. China and Israel, among others, are also working on lunar projects. And for the first time, several private groups are building spacecraft to land on the moon in an attempt to win millions of dollars in the Google Lunar X Prize. Some participants say that they plan to gain some property rights in the mission.
小題1:In the passage the writer seems to be worrying that ________.
A．the US will live on the moon forever
B．the moon will not be able to hold all mankind
C．the potential land rush will become more and more frequent
D．no one can answer the question “ Who owns the moon?”
小題2:“ The Google Lunar X Prize” aims to ________.
A．encourage private groups to land on the moon
B．help NASA host a discussion about land rush on the moon
C．help some developing countries to complete their lunar projects
D．reward some countries or private groups which haven’t stepped on the moon
小題3:The underlined word “ that” in the first paragraph refers to ________.
A．the Outer Space Treaty
B．if and when they plant a flag
C．the NASA working group
D．monks from the Middle Ages
小題4:What is the main idea of the last paragraph?
A．The U. S. astronauts will live on the moon for longer time.
B．Many countries and private groups plan to go to the moon.
C．Why some private groups wish to land on the moon.
D．It is easy to gain some property rights on the moon.
小題5:We can infer from the passage that ________.
A．it’s a waste of time to work on the lunar project
B．“ The Outer Space Treaty” forbids private groups to land on the moon
C．a(chǎn)ll mankind has the right to land on the moon
D．whenever you come to the moon, you’ll get some property rights on it

小題1:C
小題2:A
小題3:B
小題4:B
小題5:C

試題分析：本文敘述了各國及私人團體的登月計劃。都想擁有月球的主權(quán)�！豆s》規(guī)定月球及其資源是全人類的共同財產(chǎn)"，“包括月球在內(nèi)的外層星體不得由任何國家依據(jù)主權(quán)要求，通過利用或占領、或以任何其他方法據(jù)為己有�！币驗槿魏螄叶紱]有、也不能對月球主張主權(quán)。就像任何人不能對公海主張所有權(quán)一樣，對月球同樣不能主張所有權(quán)。因為那將意味著一場個人對全人類的戰(zhàn)爭。如果有人宣布月球及其宇宙星體屬于他個人，就會剝奪了全人類的共同財產(chǎn)，這其實也是一種違法行為。
+1已贊過+1已贊過小題1:細節(jié)理解題。根據(jù)space industry thought leaders are seriously asking themselves how to deal with a potential land rush.故選C。
小題2:細節(jié)理解題。根據(jù)And for the first time, several private groups are building spacecraft to land on the moon in an attempt to win millions of dollars in the Google Lunar X Prize. 為了鼓勵人們登上月球，故選A。
小題3:詞義猜測題。根據(jù)if and when they plant a flag, does，如果把旗插到月球上就能給他們財產(chǎn)權(quán)利嗎？故選B。
小題4:段意歸納題。根據(jù)本段敘述了各國或私人團體的登月計劃，故選B。
小題5:推理判斷題。根據(jù)The Outer Space Treaty, the international signed by more than 100 countries, states that the moon and other celestial bodies (天體) are the province of all mankind.月球?qū)儆谌祟�，故選C。
點評：詞義猜測題旨在考查學生根據(jù)上下文對生詞做出理解判斷的能力。近幾年來，閱讀理解中的詞義猜測題呈上升趨勢。在閱讀過程中根據(jù)選材、背景、及上下文等線索推測出生詞詞義是真實語言活動中的重要技巧。這一能力可以說是體現(xiàn)閱讀理解能力的一項重要指標。
練習冊系列答案
相關習題

科目：高中英語 來源：不詳 題型：閱讀理解

In western countries, especially in America, some social customs have lasted still today. For example, ladies first, that is to say, women in those countries are respected(尊重) in many ways.
In the U.S. and Europe, you will see men usually open doors for women and women generally walk ahead of men into a room or a restaurant unless the man have to be ahead of the ladies to choose the table, to open the door of a car or to give other services. On the street, men almost walk or across the street on the side of the ladies which is closer to traffic, but if a man walks with two ladies, he should walk between them.
小題1:In this passage， “customs” especially refers to _______.
A．what a group of people usually do
B．what people in western countries do
C．what people in eastern countries do
D．what people in united states do
小題2:When you introduce a group of people in English, you will probably begin with  _____.
A．Men and womenB．Women and men
C．Gentlemen and ladies D．Ladies and gentlemen
小題3:In which country people may think it strange that men should open doors for women?
A．EnglandB．ItalyC．JapanD．Germany
小題4:Which of the following statements is not true?
A．In Europe, a man generally follows a woman when they enter a restaurant together.
B．In America a man who walks ahead of a women always gives services.
C．In the U.S, women almost always walk closer to the running cars.
D．In the U.S, men should always walk by the side of the ladies.
小題5:Which of the following statements best expresses the main idea of this passage?
A．In western countries, some social customs have lasted till today.
B．Women in western countries are respected in many ways.
C．Men usually open doors for women in the U.S. as well as in Europe.
D．Men show respect for women by giving them good services.

查看答案和解析>>

科目：高中英語 來源：不詳 題型：完形填空

Historically, the term “fair trade” has meant many things. The Fair Trade League was  1 in Britain in 1881 to restrict 2  from foreign countries. In the United States, businesses and labor unions  3  “fair trade” laws to construct what economist Joseph Stiglitz calls “barriers to imports.” These so called “anti-dumping(反傾銷)” laws allow a company that  4  a foreign one of selling a product below cost to request that the government charge special taxes to protect it from “unfair”  5 .
Such dark protectionist thoughts are far from the  6  of the organizers of the United Kingdom’s annual “Fairtrade Fortnight”. Their  7 aim is to raise the price paid to developing-country farmers for their  8  by cutting out the inflated profits of the middlemen on whom they  9  for getting their goods to distant markets. Fair-trade products  10  cocoa, coffee, tea, and bananas do not compete with domestic European production, and  11  do not have a protectionist motive(動機).
This is how it works: In  12  for being paid a guaranteed price and meeting “agreed labor and environmental standards” (minimum wages, no farm chemicals ), poor-country farming cooperatives(合作社) receive a FAIRTRADE mark for their products, given 13  by the FAIRTRADE Labeling Organization. This mark  14  supermarkets and other businesses to sell the products at a higher than  15  price . Third-world farmers get their income increased , 16  first-world consumers get to feel virtuous: a marriage made in heaven.
The fair-trade movement,  17  in the 1980’s, has been growing rapidly. In a significant breakthrough in 1997, the British House of Commons  18  to serve only fair-trade coffee. By the end of 2007, more than 600 producers’ organizations,  19  1.4 million farmers in 58 countries, were selling fair-trade products. Today, a quarter of all bananas in UK supermarkets are sold under a FAIRTRADE mark. But FAIRTRADE-labeled products still represent a very  20 share – typically less than 1% – of global sales of cocoa, tea, coffee, etc.
小題1:
A．discoveredB．foundedC．encouragedD．promoted
小題2:
A．importsB．exportsC．outputD．trade
小題3:
A．disobeyB．breakC．useD．study
小題4:
A．suspectsB．needsC．wantsD．a(chǎn)dvertises
小題5:
A．a(chǎn)greementB．contractC．gameD．competition
小題6:
A．worriesB．mindsC．commentsD．projects
小題7:
A．educationalB．politicalC．worthyD．immediate
小題8:
A．favourB．benefitC．interestD．produce
小題9:
A．dependB．spendC．lookD．a(chǎn)pply
小題10:
A．a(chǎn)sB．likeC．withD．for
小題11:
A．insteadB．otherwiseC．thereforeD．a(chǎn)nyhow
小題12:
A．fearB．storeC．preparationD．exchange
小題13:
A．secretlyB．publiclyC．officiallyD．successfully
小題14:
A．urgesB．enablesC．ordersD．forces
小題15:
A．normalB．potentialC．lowestD．best
小題16:
A．whenB．whileC．a(chǎn)sD．but
小題17:
A．launchedB．a(chǎn)rrangedC．inventedD．developed
小題18:
A．wantedB．refusedC．hadD．decided
小題19:
A．tellingB．representingC．Choosing D．receiving
小題20:
A．smallB．littleC．goodD．large

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

BEIJING , March 9 --- The central government will require an additional three years of use for official vehicles for ministers and governors to reduce the costs of purchasing new cars, media have reported.
The new rule has been applied among all Party and government departments nationwide, the Beijing News reported on Tuesday. The new rule has not yet been made public, said Li, a member of the Chinese People’s Political Consultative Conference National Committee.
Under the old rules, the cars used by minister-level officials could be replaced as often as every five years, Li said. These officials will also keep the same cars when they assume new posts, he added.
The new rule also reiterated(重申) that officials ranking below minister-or-governor-levels should not be allocated cars. The cars possessed by their departments should be used on demand.
“It violates the rules for lower-ranking --- even county-level-officials to be allocated cars,” Li said.
Purchases of vehicles for official use have been heavily investigated, as they account for a large expenditure (花費) of public funds every year.
A survey on the Web news www.ifeng.com found 64 percent of respondents believed the new rule will be difficult to carry out because it is related to officials’ interests.
“Local government departments had halted(中斷) approvals for requests for such vehicles and had started to work on new quotas(指標) under the new rules,” Li said. “The future reform of official vehicle use will introduce market mechanisms and monetization.”
Premier Wen Jiabao said in the annual government work report on Saturday that expenditures on such vehicles will not increase in 2011 compared with a year ago.
Beijing’s standing deputy mayor Ji Lin last week said the municipal (市政的) government will release the number of vehicles for official use in the capital as early as at the end of this month.
Earlier this month, the Minister of Finance had published a rule regulating the budgets for such vehicles.
小題1:What is the purpose of the new rule allocating vehicles among officials?
A．To promote a low-carbon lifestyle.
B．To cut down the present huge expenditures of purchasing cars.
C．To make good use of budgets for official cars.
D．To solve the problem of severe traffic jam.
小題2:How often could the cars used by minister-level officials be replaced according to the new rule?
A．Every 3 years.B．Every 5 years.C．Every 8 years.D．Every 10 years.
小題3:What about the officials ranking below minister-or-governor levels in terms of official vehicles?
A．They can still possess special cars.
B．They can use their own private cars.
C．They can use cars whenever officially necessary.
D．They can be allocated second-hand cars.
小題4:What is the public’s attitude toward the new rule’s fulfillment?
A．Uncertain.B．Optimistic.C．Indifferent.D．Passive
小題5:From the passage, we can infer that_________.
A．the government is determined to carry out the new rule
B．the new rule has not yet been made public
C．the new rule will benefit official’s interest
D．the new rule is applied to minister-level officials

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

TANG Dynasty writer Du Mu once wrote in a poem titled Qingming: "The ceaseless drizzle drips all the dismal day; So broken-hearted fares the traveler on the way.Where can a wine house be found to drown his sadness ?A cowherd points to Almond Flower (Xing Hua) Village in the distance."
Qingming, the traditional tomb-sweeping day on the Chinese lunar calendar, falls on April 4 this year. Qingming Jie was proclaimed a Chinese national holiday in 2008. It is a time for remembering loved ones who have departed (去世). People visit their ancestors’ graves to sweep away the dirt and get rid of any weeds. They also leave offerings (祭品) of food and flowers, and burn incense (香) and paper money. Chinese tombs are usually built in the woods or on mountains, far from the city. It is believed that an area that faces south, with many pine trees, is a proper place for a tomb. People believe such a place will make the ancestors happy, and in return, they will look after the living family.
Nowadays, more and more residents are choosing environmental-friendly ways to spend the holiday such as flower sacrifices and memorial ceremonies on the Internet or at home. As one of the traditional ways to celebrate Tomb-sweeping Day – burning paper or incense – isn't exactly good for air quality.
In contrast to the sadness of the tomb sweepers, people also enjoy hope of Spring on this day. The Qingming Festival is a time when the sun shines brightly, the trees and grass become green and nature is again lively. Since ancient times, people have followed the custom of Spring outings. At this time tourists are everywhere.
Many people fly kites on Tomb Sweeping Day. They are usually made from a bamboo crossbow with coloured paper. The kite vibrates and buzzes as it rises into the sky, counterbalanced by its tail. Large kites can be as broad as three metres across, with a tail of six to ten metres. Most kites have a rectangular shape, and many have patterns of crabs, centipedes, butterflies, dragonflies, or Chinese characters such as "good fortune" or "long life". (361words)
小題1:What’s the main idea of the second paragraph?
A．The cultural difference between the east and the west.
B．The traditional customs on tomb-sweeping day.
C．Various ways to care for the dead in the world.
D．Qingming Festival
小題2:All of the following practices are mentioned on tomb-sweeping day EXCEPT_____ .
A．Weeping over the passed-away.
B．Flying kites made from bamboo and paper
C．Sending flowers to their ancestors’ graves.
D．Burning incense and paper money for the dead.
小題3:Which of the following is correct according to passage?
A．Du Mu ,the well-known poet in Song Dynasty wrote a poem about Qing Ming.
B．Qingming Festival used to be a Chinese national holiday.
C．People have the custom of flying kites on Qing Ming.
D．Those whose ancestors were buried in proper places will have a bright future.
小題4:The writer write the passage in order to____________ .
A．enable us to observe traditional tomb-sweeping day.
B．show traditional and present ways to spend Qingming Festival .
C．educate people to show their respect to the ancestors
D．raise people’s awareness of environmental protection.

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

The aims of the Illustrators’(插圖畫家的) Exhibition, staged as part of the Bologna Children’s Book Fair, organized by BolognaFiere and held from 23 to 26 December 2012, are to bring illustrators and publishers together and to promote illustrators and their works among publishers.
QUALIFICATIONS
? Individual illustrators or groups of illustrators of any nationality, if they were born before 31st December 1992, whose artwork is intended for use in children’s books, are qualified to enter the Exhibition, either directly or through publishing houses or schools.
? Please state in the application form whether you are entering work for the Fiction or Nonfiction Category. Illustrators may only enter one category.
? Artwork previously presented to the Exhibition may not be re-entered.
? The confirmation(確認) form must be filled in and a photograph attached, then presented together with illustrations no later than 15 October 2012.
SHIPMENT
Entries may be delivered by post, express delivery service or by hand. From abroad, please use the following forms: Form “A” for registered mail or post by air; Form “B” if using an international forwarding agent or airline.
To avoid delays, material should not be sent by normal post. Material should be sent “carriage(運費) paid”, including any customs and delivery costs.
BolognaFiere may not be held responsible for the non-arrival or late arrival of artwork. All published works must be accompanied by a declaration bearing the ISBN number, publisher’s name and address.
REQUIREMENTS
The illustrations (i.e. the size of the sheet) must not exceed(超過) the following dimensions:
Fiction:
32 × 42 cm (or 42 × 32 cm)
Non-fiction:
50 × 70 cm (or 70 × 50 cm)
Illustrations in larger formats will not be considered, nor will they be returned by BolognaFiere. The illustrations must be on paper or flexible board, maximum thickness 2 mm (for scanner separation purposes).
SELECTION PROCESS
All artwork received by the stated deadline and meeting the specified requirements will be examined and selected by an international group (whose decision is final), including five members (from publishing house and art schools) appointed each year by BolognaFiere.
EXHIBITIONS ABROAD
After the Bologna event, the Illustrators Exhibition will travel to Japan under the supervision of JBBY. The Illustrators Exhibition may afterwards be transferred to other venues(場館) in other countries. The exhibitions of illustrations held abroad follow the same rules and regulations as the Illustrators Exhibition, and the provisions(條款) of the regulations are extended to the organizers of the exhibitions held abroad.
RETURN OF ARTWORK
All the works will be returned to their owners by BolognaFiere or directly by the organizers of the exhibitions and held abroad by the end of July 2013.
小題1:Which of the following of the Illustrators’ Exhibition is TRUE?
A．It will last five days in all in July every other year.
B．It is intended for college students who are good at painting.
C．It is held by the Bologna Children’s Book Fair in BolognaFiere.
D．It can strengthen the relationship between illustrators and publishers.
小題2:The illustrators of the Illustrators’ Exhibition ______.
A．should be at least 16 and no more than 25
B．may re-enter their artwork after it is returned
C．should state the category of their artwork clearly
D．may choose to attach a photo to the application form
小題3:Which of the following is unacceptable for delivering entries?
A．Normal post. B．Airline post. C．Registered mail. D．Express delivery.
小題4:What is BolognaFiere responsible for?
A．Paying for the delivery costs.
B．Late arrival of artwork.
C．Confirmation of ISBN number.
D．Returning the illustrators’ works.
小題5:The illustrators’ works will not be considered if they ______.
A．a(chǎn)re received after the day of 15 October 2012
B．a(chǎn)re smaller than the required size
C．have already been published abroad before
D．don’t meet the demands of the international experts

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

It may seem to be a hard task to trace back the history of rap music, though you often see the informal music associated with highly informal dance style. As far as the origin of rap music is concerned, most people agree that it is from Afro-American and Latino Street culture of New York City. Not only in this city but in the surrounding areas there is the influence of African people and their culture.
Rap is a vocal (口頭的) style in which the performer speaks rhythmically and in rhyme, generally to a beat. The term of rap music is the same with hip-hop music typically-consisting of a rhythmic vocal style called rap. If we see it carefully, then we will definitely notice that the music usually is sung at higher pitches (調(diào)). Most of the time rap music is associated with chorus. Though rap music was primarily an American music style with African influence over its music and lyrics, recently it has been spread to almost the entire world.
There is hardly any country or nation where rap music cannot be seen in some form or another, and it is one of the most popular music styles among the youngsters. However, when it comes to its history, it is believed that hip-hop or rap music started in the early 1970s，and gained much popularity throughout the world during the late 1970s and early 1980s.
The history of rap music and hip-hop music is full of controversies (爭議) and bans, as the lyrics sometimes relate to drugs and crime; even most famous pop stars and hip-hop musicians and singers were found to be associated with the controversies in their life. For that reason, no matter how popular this music style was or still is, it has always had a bad reputation in the eyes of mainstream society.
小題1:The passage is mainly about _____.
A．when rap music started B．how rap music develops
C．what rap music is like D．why rap music is popular
小題2:The characteristics of rap music are _____.
A．solo, rhymes，beats and pops
B．speaking, rhythms，beats and solo
C．repeating, speaking, pops and chorus
D．speaking, rhymes, beats and chorus
小題3:Rap music is now one of the music styles mostly run after by _____.
A．the teenagers in Africa
B．a(chǎn)ll kinds of people in the world
C．the youngsters all over the world
D．the young people in the US
小題4:Rap music is often not well thought of by the mainstream because _____.
A．it comes from the lower class
B．it has a short history
C．it is associated with crimes and drugs
D．its music is full of controversies

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

The porter(行李搬運工) brings your bags to your room and helpfully explains all you want to know．Then he points to the phone and says：“If there’s anything else you need, just call．”All this time you have been thinking of one thing：“How much should I tip(付小費)him?” To make your next trip a little easier, here’s guide to tipping across some Asian countries.
Bangkok(曼谷)
In general, the more westernized the place is, the more likely you will be expected to leave a tip．Some top-end restaurants will add a 10％ service charge to the bill．If not, waiters will appreciate your tacking on(附加)the 10％ yourself．However, if you’re eating at a lower-end restaurant, a tip is not necessary．If you’re staying at one of Bangkok’s many five-star hotels, expect to tip the porter 20 to 50 baht(泰國貨幣單位),depending on how many bags you have．Taxis are now metered in Bangkok．Local custom is to round up(湊整數(shù))the fare to the nearest five baht．
Hong Kong
Tipping is customary in this money-mad metropolis(大都市)．Most restaurants add a 10％ service charge to the bill, but the extra money often ends up in the pocket of the owner. If the service is good, add another 10％ to the bill, up to HKMYMl00 in an especially nice restaurant．For HK MYM10 hotel porters should do it at all but the nicest hotels where a new HKMYM20 bill may be more acceptable．When in a taxi, round up to the nearest dollar．
Kuala Lumpur（吉隆坡）
Tipping in Malaysia is limited to the expensive westernized hotels, which often add a 10％ service charge to your meal or hotel room．If you are at a hotel restaurant, expect a 10％ service charge．
But at local restaurants, there’s no need to add a tip. At five-star hotels, one or two ringgit(馬來西亞貨幣單位)will satisfy a porter. At lower-end buildings don’t feel you have to tip Like Bangkok, many taxis are now metered so you can just round up to the nearest ringgit．
Seoul
Tipping is not part of Korean culture, although it has become a matter of course in international hotels where a 10％ service charge is often added．If you’re at a Korean barbecue joint(燒烤處), there’s no need to add anything extra．But a nice Italian restaurant may require a 10％ contribution．
If you’re at a top-end hotel, so expect to pay 500～l,000 won per bag．Taxi drivers don’t accept a tip．Keep the change for yourself．
小題1:Which of the following is NOT the unit of money?．
A．ChargeB．BahtC．WonD．Ringgit
小題2:In which of the following cities is it unnecessary to tip the taxi-drivers?
A．BangkokB．HongkongC．Kuala LumpurD．Seoul
小題3:If you stay at a five-star hotel in Kuala Lumpur, how much will you pay the porter at least?
A．10％ of service chargeB．Three ringgitC．Half a ringgitD．One ringgit
小題4:The writer seems           ．
A．to tell the readers how to travel
B．to give the readers some advice on how to tip
C．to ask the readers to go on a travel to Asian cities
D．to make the trip more pleasant

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

Many English learners have difficulty deciding what kind of English accent they want to have． A US accent, perhaps modeled on the way a Hollywood star speaks? Or maybe you want to imitate（模仿） the British accent of a BBC news reader?
Young British people find the US accent attractive while young US people like a British accent． Especially when the person speaking is of the opposite sex(異性)! Let’s listen to what they have to say．
Stephen Yang, 17, from London, UK
A US accent is cute, especially when a girl speaks it． Whether it’s Jessia Alba speaking or the girl- next-door, the way US girls speak has a sweet tingle that is really sassy(時髦)． A girl from Texas recently moved into our neighborhood． Her Texan twang（鼻音） had all the boys here on their knees within seconds of meeting her．
To me, accents reflect the attitudes, characteristics and lifestyles of the people．
Jennifer Sun, 16, from New Jersey, US
From watching English actors like Daniel Radcliffe, my friends and I have developed a soft spot for British men．Some are attracted to the qualities of English males, while others admire their sense of style．
Everyone, however, agrees that the most appealing aspect of an English man is his accent． For example, many American girls watch Harry Potter movies over and over again just to listen to the actors speak．
The English accent seems almost like art．
小題1:In Stephen Yang’s opinion, accents just show__________．
A．the beauty of the language
B．how the language is spoken
C．the cultural differences of the speakers
D．the meeting of the day
小題2:The underlined sentence in paragraph means that __________．
A．All the boys broke their knees
B．All the boys fell to the ground
C．All the boys liked her accent very much
D．All the boys imitated（模仿）her accent
小題3:Many American girls watch Harry Porter again and again in order to __________．
A．learn the acting skills of the these stars
B．learn the magic performed by Harry Potter
C．imitate the actors’ accents
D．know more about British English
小題4:What is probably the best title for this passage?
A．British English and American English
B．British Accent or American Accent
C．American English Accent is Most Accepted
D．The difference between British Accent and American Accent．

查看答案和解析>>

同步練習冊答案