试题

试题 试卷

logo

题型:任务型阅读 题类:模拟题 难易度:普通

浙江省杭州市翠苑中学2018年英语中考二模试卷

下面文章中有五处需要添加小标题。请从以下选项(A、B、C、D、E和F)中选出符合各段意思的小标题。选项中有一项是多余选项。

A. It is very hard to break a code without the code book.

B. Only people who know the keyword can read the message.

C. As long as there have been codes, people have tried to break them.

D. You can hide a message by having the first letters of each word spell it out.

E. With a code book, you might write down words that would stand for other words.

F. Another way to hide a message is to use symbols to stand for specific letters of the alphabet.

    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. 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. For example, the first letters of "My elephant eats too many eels" Spell out the hidden message "Meet me."

    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, 5, 20, 15, 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.  For example, "bridge" might stand for "meet" and "out" might stand for "me." The message "bridge out" would actually mean "Meet me."  However, it is also hard to keep a code book secret for long. So codes must be changed frequently.

举一反三
返回首页

试题篮