Secret codes (密码) keep messages private. Banks, companies, and government agencies use secret codes in doing business, especiall

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问题     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.【R1】________. Code breaking never lags (落后) far behind code making. The science of creating and reading coded messages is called cryptography.
    There are three main types of cryptography.【R2】________. For example, the first letters of "My elephant eats too many eels" spell out the hidden message "Meet me."
    【R3】________. You might represent each letter with a number, For example. Let’s number the letters of the alphabet, in order, from I 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.【R4】________. For example, "bridge" might stand for "meet" and "out" might stand for "me." The message "bridge out" would actually mean "Meet me."【R5】________. 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.
【R2】

选项

答案E

解析 过渡句。上句提到:有三种主要的密码设定方式。下句提到:例如My elephant eats too many eels的首字母就拼出了Meet me这一隐藏起来的信息。由此可知本句应该为一种密码的设定方式,根据下句举出的例子,可知E项正确,意为“可以用每个单词的首字母拼写出一条信息,以此来隐藏它。”故选E。
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本试题收录于: 英语题库普高专升本分类
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