Question

【题目】Choose the best answer and complete the passage （选择最恰当的选项完成短文）

Secret codes 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. As long as there have been codes, people have tried to break them. Code breaking never ______ code making. The science of creating and reading coded messages is called cryptography（密码系统）.

There are three main types of cryptography. You can ______ a message by having the first letters of each word spell it out. For example, the first letters of “My elephant eats too many eels（鳗）” spell out the message “Meet me.”

Another way is to use symbols to ______ specific letters of the alphabet. 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 replace each letter with a number, the message “Meet me” would read “13, 5, 5, ______, 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. With a code book, you might write down words that would be ______ as other words. For example, “bridge” might refer to “meet” and “out” might mean “me.” The message “Bridge out” would have meaning of “Meet me”. It is very hard to break a code with out the code book. Actually, it is also hard to keep a code book secret for long. ______, codes must be changed frequently.

【1】A.goes aheadB.takes the place ofC.falls behindD.depends on

【2】A.sendB.takeC.translateD.hide

【3】A.stand forB.make upC.deal withD.find out

【4】A.17B.18C.19D.20

【5】A.explainedB.misunderstoodC.rememberedD.acted

【6】A.HoweverB.ThereforeC.In additionD.Otherwise

Answer 1

【答案】

【1】C

【2】D

【3】A

【4】D

【5】A

【6】B

【解析】

本文属于说明文，主要介绍了几千年来密码的主要类型以及设置密码的方法并嘱咐我们设置密码的方式以及要经常更改密码才是最有效的方法．

【1】句意：代码破解永远不会落后于代码生成。

考查动词短语辨析。goes ahead继续；takes the place of取代；falls behind落后；depends on取决于。根据“As long as there have been codes, people have tried to break them.”只要有密码，人们就试图破解它们。可知，下文是说代码破解永远不会 _______ 于代码生成。因此应该选择falls behind落后；符合语境。故选C。

【2】句意：你可以通过让每个单词的第一个字母拼出来隐藏的信息。

考查动词辨析。send发送；take获取；translate翻译；hide隐藏。根据“For example, the first letters of “My elephant eats too many eels（鳗）” spell out the message “Meet me.””例如，“我的大象吃太多鳗鱼”的第一个字母拼出来的信息是“见我”。可知，这是隐藏信息的一个例子。故选D。

【3】句意：另一种方法是使用符号来代表字母表中的特定字母。

考查动词短语。stand for代表；make up编造；deal with处理；find out发现。根据“If we replace each letter with a number, the message “Meet me” would read “13, 5, 5, ___4___, 13, 5.””如果我们用一个数字来替换每一个字母，那么“遇见我”的信息将是“13，5，5，_______，13，5”可知，这是用数字代表字母。因此上句话应该是另一种方法是使用符号来代表字母表中的特定字母。故选A。

【4】句意：如果我们用一个数字来替换每一个字母，那么“遇见我”的信息将是“13，5，5，20，13，5”。

根据“Let’s number the letters of the alphabet, in order, from 1 to 26.”让我们把字母表中的字母从1到26按顺序编号。可知，13就代表m；5就代表e；因此t就可以用20来代替了。因此：meet me的信息就是：“13，5，5，20，13，5”了。故选D。

【5】句意：有了一本代码手册，你可以写下可以解释为其他单词的单词。

考查动词辨析。explained解释；misunderstood误解；remembered记忆；acted行动。根据“For example, “bridge” might refer to “meet” and “out” might mean “me.” The message “Bridge out” would have meaning of “Meet me”.”例如，“bridge”可能指“meet”，“out”可能指“me”，“bridge out”的意思是“meet me”。可知，这是用一个单词解释另一个单词。故选A。

【6】句意：因此，代码必须经常更改。

考查副词辨析。However 然而；Therefore因此，是副词，但有时具有连词作用；In addition另外；Otherwise否则。根据“Actually, it is also hard to keep a code book secret for long.”实际上，要长期保守密码本的秘密也是很困难的。可知，下文应该是：因此，代码必须经常更改。所以应该选择Therefore；Therefore在整句中时一般不放句末，句首后要有逗号。故选B。

本题的第4小题是要求填数字的。首先弄明白句子Let’s number the letters of the alphabet, in order, from 1 to 26.的含义，即：26个字母与数字1—26的对应；也就是1对应a；2对应b；依次类推。13就对应m；5就对应e；因此t就对应20了。所以：meet me的信息就是：“13，5，5，20，13，5”了。故选D。