第二節(jié)(共5小題;每小題2分，滿分10分)

　　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。

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

　　People have used secret codes for thousands of years. 

　　36 Code breaking never lags (落后) behind code making. The science of decoding and reading coded messages is called cryptography.There are three main types of cryptography.

　　37 For example, the first letters are “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 “1 3 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.

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

　　36.【解析】D

　　本題考察是邏輯關(guān)系，根據(jù)下一句“code breaking never lags behind code making”可知上一句是只要出現(xiàn)密碼，就會有人去解碼，故選D。

　　37.【解析】E

　　本題考察是句子之間的例證關(guān)系，從后面文章的舉例中“For example, the first letters are ‘My elephant eats too many eels’ spell out the hidden message ‘Meet me.’ ”那么前一句應(yīng)該是對例子的概括，即我們可以知道是運用每個單詞的首字母來組成密碼，E選項正確

　　38.【解析】G

　　本題考察是文章的篇章結(jié)構(gòu)，前一段是講到了第一種方法，根據(jù)篇章結(jié)構(gòu)，下一段應(yīng)該是講述第二種設(shè)置密碼的方法，而根據(jù)該段的例子，即字母表中字母排列順序轉(zhuǎn)化成為數(shù)字信息，所以這里關(guān)鍵詞是another way 還有alphabet，故選G。

　　39.【解析】F

　　本題考察的是邏輯關(guān)系，從上一句“To read the message of a real code, you must have a code book ”你需要借用解碼書來找出密碼單詞所對應(yīng)真正意思，F(xiàn)選項表示你應(yīng)該找出解碼書中密碼所代表的詞語，故F正確。

　　40.【解析】A

　　本題考察的是關(guān)鍵詞以及轉(zhuǎn)折關(guān)系，根據(jù)下一句出現(xiàn)“it is also hard to keep a code book secret for long, ” 這里出現(xiàn)了also hard,所以上一句關(guān)鍵詞為hard;另外however表示轉(zhuǎn)折關(guān)系，證明上一句與下一句表達(dá)的意思相反，即上一句應(yīng)該沒有解密書，是很難去完成解密工作，故A正確。