Question

【題目】Choose the best answer and complete the passage （選擇最恰當的選項完成短文）

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（密碼系統(tǒng)）.

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（鰻）” 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】

本文屬于說明文，主要介紹了幾千年來密碼的主要類型以及設置密碼的方法并囑咐我們設置密碼的方式以及要經常更改密碼才是最有效的方法．

【1】句意：代碼破解永遠不會落后于代碼生成。

考查動詞短語辨析。goes ahead繼續(xù)；takes the place of取代；falls behind落后；depends on取決于。根據“As long as there have been codes, people have tried to break them.”只要有密碼，人們就試圖破解它們�？芍�，下文是說代碼破解永遠不會 _______ 于代碼生成。因此應該選擇falls behind落后；符合語境。故選C。

【2】句意：你可以通過讓每個單詞的第一個字母拼出來隱藏的信息。

考查動詞辨析。send發(fā)送；take獲�。�translate翻譯；hide隱藏。根據“For example, the first letters of “My elephant eats too many eels（鰻）” spell out the message “Meet me.””例如，“我的大象吃太多鰻魚”的第一個字母拼出來的信息是“見我”�？芍�，這是隱藏信息的一個例子。故選D。

【3】句意：另一種方法是使用符號來代表字母表中的特定字母。

考查動詞短語。stand for代表；make up編造；deal with處理；find out發(fā)現。根據“If we replace each letter with a number, the message “Meet me” would read “13, 5, 5, ___4___, 13, 5.””如果我們用一個數字來替換每一個字母，那么“遇見我”的信息將是“13，5，5，_______，13，5”可知，這是用數字代表字母。因此上句話應該是另一種方法是使用符號來代表字母表中的特定字母。故選A。

【4】句意：如果我們用一個數字來替換每一個字母，那么“遇見我”的信息將是“13，5，5，20，13，5”。

根據“Let’s number the letters of the alphabet, in order, from 1 to 26.”讓我們把字母表中的字母從1到26按順序編號。可知，13就代表m；5就代表e；因此t就可以用20來代替了。因此：meet me的信息就是：“13，5，5，20，13，5”了。故選D。

【5】句意：有了一本代碼手冊，你可以寫下可以解釋為其他單詞的單詞。

考查動詞辨析。explained解釋；misunderstood誤解；remembered記憶；acted行動。根據“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”�？芍�，這是用一個單詞解釋另一個單詞。故選A。

【6】句意：因此，代碼必須經常更改。

考查副詞辨析。However 然而；Therefore因此，是副詞，但有時具有連詞作用；In addition另外；Otherwise否則。根據“Actually, it is also hard to keep a code book secret for long.”實際上，要長期保守密碼本的秘密也是很困難的�？芍�，下文應該是：因此，代碼必須經常更改。所以應該選擇Therefore；Therefore在整句中時一般不放句末，句首后要有逗號。故選B。

本題的第4小題是要求填數字的。首先弄明白句子Let’s number the letters of the alphabet, in order, from 1 to 26.的含義，即：26個字母與數字1—26的對應；也就是1對應a；2對應b；依次類推。13就對應m；5就對應e；因此t就對應20了。所以：meet me的信息就是：“13，5，5，20，13，5”了。故選D。