Question

【題目】 David’s got a text message from his friend Sam. Can you understand it?

7,15 20,15 20,8,5 16,1,18,11

This message was in code(密碼，代碼). How many letters are there in the English alphabet?

Twenty-six. So can you read it now?

A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	P	Q	R	S	T	U
1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21

David decided to use a different code in his answer to Sam. This time, he was putting A instead of B, B instead of C, and so on. His message to Sam shown on the right was very short. Can you understand?

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

A

Sam guessed David’s code, and he replied: ZESDQ RBGNNK. When David’s little sister saw the message, she felt puzzled. She couldn’t read it at all. But David was very happy that his sister couldn’t read his message!

Lots of people use codes to send secret messages. In a war, secrets are very important so soldiers often send each other messages in code. Nowadays, we can use computers to make and break difficult codes. Even before computers, people invented other machines to do this.

Here’s a famous machine that Germans used in the Second World War (1941-1945). It’s called the Enigma Machine. The machines were very big, heavy and expensive. Every day they changed the codes automatically, and this made it almost impossible for anyone to break the codes. The person sending a message had one machine, and the person receiving the message had another.

【1】Sam asked David to go to the ________.

A.parkB.houseC.museumD.zoo

【2】Sam told David to meet him

A.before breakfastB.after schoolC.after dinnerD.before school

【3】Codes are used to keep something_________.

A.newB.oldC.secretD.known

【4】People will never know the meaning if they can’t _______ the code.

A.breakB.makeC.changeD.write

【5】The best title of this passage is _______.

A.English LettersB.CodesC.MessagesD.Machines

Answer 1

【答案】

【1】A

【2】B

【3】C

【4】A

【5】B

【解析】

本文是一篇說(shuō)明文，由大衛(wèi)和薩姆之間互傳密碼信息引入，介紹了人們使用密碼的歷史、背景等。

【1】推理判斷題。根據(jù)This message was in code. How many letters are there in the English alphabet?可知該密碼用26個(gè)英文字母對(duì)應(yīng)的數(shù)字來(lái)構(gòu)成，薩姆的數(shù)字密碼對(duì)應(yīng)成相應(yīng)順序的字母連起來(lái)意為go to the park，故選A。

【2】推理判斷題。根據(jù)This time, he was putting A instead of B, B instead of C, and so on，可知回復(fù)的信息所用密碼每個(gè)字母都往前推了一位，復(fù)位則要往后推回來(lái)，大衛(wèi)的密碼復(fù)位后是after school，故選B。

【3】細(xì)節(jié)理解題。根據(jù)Lots of people use codes to send secret messages，可知是為了保守秘密，故選C。

【4】細(xì)節(jié)理解題。根據(jù)Every day they changed the codes automatically, and this made it almost impossible for anyone to break the codes，可知不破解密碼就不能知道它的意思，故選A。

【5】最佳標(biāo)題。通讀全文，可知文章主要由大衛(wèi)和薩姆之間互傳密碼信息引入，介紹了有關(guān)密碼的事情，故選B。