根据短文内容，从短文后的选项中选出能填入空白处的最佳选项，选项中有两项为多余选项。

      Secret codes (密码)keep messages private。Banks, companies, and government agencies use secret codes in doing business, especially when information is sent by computer.

     People have used secret codes for thousands of years. {#blank#}1{#/blank#}  Code breaking never lags(落后) far behind code making. The science of creating and reading coded messages is called cryptography.

     There are threemain types of cryptography. {#blank#}2{#/blank#}  For example, the first letters of “My elephant eats too many eels” Spell out the hidden message “Meet me.”

{#blank#}3{#/blank#} You might represent each letter with a number, For example, Let's number the letters of the alphabet, in order, from 1 to 26. If we substitute a number for each letter, the message “Meet me” would read “13 5 20 13 5.”

     A code uses symbols to replace words, phrases, or sentences. To read the message of a real code, you must have a code book. {#blank#}4{#/blank#} For example “bridge“ might stand for “meet” and “out” might stand for “me.” The message “bridge out” would actually mean “Meet me.” {#blank#}5{#/blank#}  However, it is also hard to keep a code book secret for long. So codes must be changed frequently.

A. It is very hard to break a code without the code book.
B. In any language, some letters are used more than others.
C. Only people who know the keyword can read the message.
D. As long as there have been codes, people have tried to break them.
E. You can hide a message by having the first letters of each word spell it out.
F. With a code book, you might write down words that would stand for other words.
G. Another way to hide a message is to use symbols to stand for specific letters of the alphabet.

    As data and identity theft becomes more and more common, the market is growing for biometric(生物测量)technologies—like fingerprint scans—to keep others out of private e-spaces. At present, these technologies are still expensive, though.

    Researchers from Georgia Tech say that they have come up with a low-cost device(装置)that gets around this problem: a smart keyboard. This smart keyboard precisely measures the cadence(节奏)with which one types and the pressure fingers apply to each key. The keyboard could offer a strong layer of security by analyzing things like the force of a user's typing and the time between key presses. These patterns are unique to each person. Thus, the keyboard can determine people's identities, and by extension, whether they should be given access to the computer it's connected to—regardless of whether someone gets the password right.

    It also doesn't require a new type of technology that people aren't already familiar with. Everybody uses a keyboard and everybody types differently.

    In a study describing the technology, the researchers had 100 volunteers type the word "touch" four times using the smart keyboard. Data collected from the device could be used to recognize different participants based on how they typed, with very low error rates. The researchers say that the keyboard should be pretty straightforward to commercialize and is mostly made of inexpensive, plastic-like parts. The team hopes to make it to market in the near future.

    As the old saying goes, "Don't judge a book by its cover." And neither should we judge movie stars by their ages. At just 21, Elle Fanning made history by becoming the youngest jury (评审团) member at the Cannes Film Festival. This year it lasted from May 14th to May 25th. "I was in complete shock when I got that phone call and that question if I wanted to be a member of the Cannes Jury," Fanning said during a press conference.

    As it turned out, it not only shocked the US actress, but also brought criticism from those who believed Fanning was too young compared to other veterans in the industry. But Fanning's acting experience was in fact a good argument for her jury membership. In fact, Fanning has been a Hollywood fixture for longer than you realize.

    The 21­year­old has been in many big productions. She began acting in I Am Sam at age 2. With lead roles in movies like Super 8, We Bought a Zoo and Maleficent under her belt (取得成功), she's appeared in 60 projects and is one of Hollywood's hottest young stars. Fanning's devotion to work numbers her among the few former child stars who continue to act as adults.

    In her latest movie Teen Spirit, which hit US cinemas last month, Fanning plays a pop singer. Since she had no singing experience, Fanning had to work with Grammy­winning music producer Marius de Vries for three months before the filming started. "I would go to his apartment and sing through all the songs every day," she said. "He videoed me and recorded me singing everything and made me watch it back again and again to improve my skills."

    With such rich acting experience and devotion to her art, "Fanning certainly was able to represent a new class in film" at the Cannes Film Festival.

    Earlier this month, two rock climbers achieved what many thought impossible: They climbed up the 3,000-foot-high Dawn Wall in Yosemite National Park without specialized equipment. Climbing without this equipment is called "free-climbing." Until now, no one had free-climbed to the top of the rock face, which is a part of the mountain EI Capitan.

    EI Capitan, which means "the captain" or "the chief" in Spanish, has always presented a challenge to climbers. But the Dawn Wall, on the mountain^'s southeast face, is a particularly difficult route to the summit (顶峰). It is a rock formation that is both steep and relatively smooth. This makes free-climbing the rock face seem almost impossible.

    About seven years ago, professional climber Tommy Caldwell spotted a possible route up the wall. It took years of planning and preparation, but this month, Caldwell, 36, and his friend Kevin Jorgeson, 30, finally make the climb.

    Free climbers do use ropes and other basic safety equipment to catch them if they fall — and Caldwell and Jorgeson fell often. Before starting their climb, they broke down their route into 32 sections. Each section was based on a rope length called a "pitch." The rope was secured into the rock face to catch the climbers if they fell.

    Caldwell and Jorgeson's goal was to climb the Dawn Wall without returning to the ground. If they fell, they had to start that pitch all over again. The two men started climbing on December 27. They slept in hanging tents, and a team of friends brought them food each day.

    The men had spent years rehearsing (排练) the movements it would take to get through each pitch. They made it through the first half of the climb relatively easily. But halfway up, Jorgeson ran into trouble. In one difficult spot, he fell each time he attempted to climb. After 10 days of trying, Jorgeson finally made it to the next pitch.

    Getting through that troublesome pitch gave both climbers renewed energy. They finished the rest of the climb five days later, on January 14.

    Chester is one of the best cities in the UK. As soon as you arrive in Chester you will appreciate the city's unique atmosphere and sense of history. Founded by the Romans over 2,000 years ago, much of the Roman influence remains and Chester's city walls are the most complete in Britain. Combined with history and heritage(遗产), Chester is a dynamic city full of bars, pubs, clubs, hotels and restaurants for you to discover, tempting you to visit again and again.

    Travelling to Chester?

    Chester is easily accessible by many means of transport — whether you are travelling by rail, car, bus or plane. Please check our route planner below to help you plan your journey to Chester. Once you arrive in the city there are numerous car parks; however, during rush hours the easiest way to travel in Chester city centre is via park and ride facilities, which are parking lots with public transportation.

    Hotels?

    From bed & breakfasts to the luxury of Chester's only five star hotel, Chester has all covered. Whether your trip is for business or pleasure your room is just a click away!

    Sightseeing and Tours?

    One of the best ways to see Chester is by a guided tour and you have a variety to choose from. Whether you choose the traditional guided walk, to be guided around Chester's historical landmarks by bus or to take a boat down the River Dee, you will sure enjoy the delights of Chester.