根據(jù)短文內(nèi)容，從短文后的選項中，選出能填入空白處的最佳選項。選項中有兩項為多余選項。

Last month, students from one hundred and three universities in eighty-eight countries took part in an international computer programming contest. The Battle of the Brains took place in Harbin, China.    71    

Jerry Cain, coach of Stanford University Team, California, says “One of the programming problems was trying to figure out how to break an arbitrary chocolate bar into a certain number of pieces of a certain number of sizes and to do it as quickly as possible.    72    ”

The students first listed the problems in order of difficulty.  73  They designed ways to test their solutions. And they wrote needed software systems. Even the winning team form Shanhai Jiaotong University in China was not able to solve all the problems within the given time limit. Stanford’s team solved five problems and finished in 14th place. Stanford was one of twenty-one American universities that took part in the contest this year.

    74    It began in 1970 at Texas A and M University. The contest quickly became popular in the United States and Canada. It developed and grew as more and more schools took part in local and area contests.

The first final competition was held in 1977 at the Association for Computer Machinery Computer Science Conference. Today, a network of universities holds area competitions that send the winners to the world finals, now organized by IBM. Contest spokesman Doug Heintzman says the world champions receive prizes and scholarships.    75   

A．The competitors show great interest in IBM.

B．Then they figured out the requirements of each.

C．And that’s probably the simplest of all of them.

D．This competition is an opportunity to be recognized by famous universities from the world.

E．Three-person teams from each school had five hours to solve eleven real world problems.

F．The official name of the Battle of the Brains is the ACM International Collegiate Programming Contest.

G．They are also guaranteed and offer of employment with IBM.

We have every reason to believe that       2010 World Expo in Shanghai will be       success．

         A．/; a     B．the; / C．the; a          D．a(chǎn); a

— Have you seen Mike these days?

   — Yes. I saw him the day before yesterday. In fact, I ______ him for three years.

  A. didn’t see         B. haven’t seen        C. hadn’t seen         D. don’t see

The headmaster will __________ a speech to the visiting foreign guests this afternoon.

       A．deliver     B．a(chǎn)ddress     C．a(chǎn)nnounce  D．declare

_____60 miles a day，you need your mountain bike in a very good state.

A．Cover    B．Covered    C．To cover     D．Having covered

C

Jiang Nan, a full-time mother in Beijing, keeps a dozen or so cloth bags at home, carefully selecting one or two before heading out to get groceries. “Most of them were giveaways from advertising marketing campaigns, but

others had been handed out in the street by various environmental protection organizations,” she explained.

Since June 2008 China has forbidden the production,

sale and usage of plastic bags thinner than 0.025 millimeter (毫米), and retailers(零售商) are not allowed to provide free plastic bags to their customers, regardless of the thickness.

Many Chinese consumers like Jiang have learned to refuse plastic bags whenever possible in their shopping. “A plastic bag may only cost a few jiao, but it’s more about how bad they are for the environment,” Jiang said.

The plastic ban is for the most part well carried out in big cities, and has been distinctly effective in reducing white waste. On the first anniversary of the plastic ban Global Village of Beijing, an NGO environmental organization, shows that during the year of the ban the consumption of plastic bags fell by about 40 billion pieces in chain supermarkets alone, saving more than 1.2 million tons of petroleum.

However, enforcement shows considerably less muscle in smaller cities, towns and country-

side. In a remote town like Lichuan, the awareness of environmental protection is not as strong as that in big cities. Street vendors(街頭小販) worry that they are likely to lose customers if they charge them for plastic bags. Seeing no significance in the issue, local government often turn a blind eye to banned bag traffic in the market.

There are still those who don’t have an interest in living green. Cui Lin, another Beijinger, often forgets to bring a cloth bag when shopping, and has to buy plastic bags. “Anyway I think plastic bags are neater and cleaner, and I don’t mind paying a couple more jiao,” he shrugged.

Mrs Yu, a vegetable vendor in Lichuan County, Jiangxi Province, recalled that before plastic bags became popular in the early 1990s, Chinese people always carried a bamboo basket when they visited the market. “Plastic bags are more convenient,” she comments, and her view might be that of the tens of millions of people in the nation who still cling to plastic bags, paid or free. This is suggested by her trade where piles of plastic bags are still passed out every day.

49. In Paragraph 1, the writer uses Jiang Nan’s case to __________.

How did Jiang Nan get her cloth bags? 

51. Which is NOT the reason why some people still use plastic bags when shopping?

52. What message does the writer mostly convey in the passage?

 Michael ________ football regularly for many years when he was young.

I do not intend to follow that, because we shall have an opportunity to do so on another __________ .

A. occasion                   B. situation            C. condition           D. environment

The doctor’s first reaction was a strange ______ of joy and anger.

A. mass                   B. mixture               C. collection              D. number

The telephone rang but I didn’t hear it. I _________ asleep.

  A. must be         B. ought to have been  C. should be          D. must have been