人教2003课标版《Using LanguageⅠ》精品PPT课件优质课下载

人教2003课标版《Using LanguageⅠ》精品PPT课件优质课下载

There are three main types of cryptography. 37 For example, the first letters of “My elephant eats too many eels” Spell out the hidden message “Meet me.”

38 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. 39 For example, ”bridge“ might stand for “meet” and “out” might stand for “me.” The message “bridge out” would actually mean “Meet me.”40 However, it is also hard to keep a code book secret for long. So codes must be changed frequently.(2016年全国卷1卷)

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.

D

E

A

F

G

考情分析

年份

卷别

体裁

题材

短文长度

是否有标题

2016

课标卷 I

说明文

密码的编制方法和破译

289

无标题

课标卷 II

说明文

为什么要种植花木以及如