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

B. Only people who know the keyword can read the message.

C. As long as there have been codes, people have tried to break them.

D. You can hide a message by having the first letters of each word spell it out.

E. With a code book, you might write down words that would stand for other words.

F. Another way to hide a message is to use symbols to stand for specific letters of the alphabet.

    Secret codes (密码)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. {#blank#}1{#/blank#}Code breaking never lags(落后) far behind code making. The science of creating and reading coded messages is called cryptography.

    There are three main types of cryptography. {#blank#}2{#/blank#}For example, the first letters of "My elephant eats too many eels" Spell out the hidden message "Meet me."

    {#blank#}3{#/blank#}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, 5, 20, 15, 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. {#blank#}4{#/blank#} For example, "bridge" might stand for "meet" and "out" might stand for "me." The message "bridge out" would actually mean "Meet me." {#blank#}5{#/blank#} However, it is also hard to keep a code book secret for long. So codes must be changed frequently.

Country：Cuba    Name：Rita

Age(年龄)：13    Favorite color：blue        Tel：8288—9765

Country：America    Name：Jenny

Age：11    Favorite color：yellow     Tel：8302—5430

Country：China    Name：Liu Yang

Age：14    Favorite color：black       Tel：8706—7459

Information Card

The country Rita comes from {#blank#}1{#/blank#}.

The age of Jenny {#blank#}2{#/blank#}.

The first name of Liu Yang {#blank#}3{#/blank#}.

The person(人)who likes yellow {#blank#}4{#/blank#}.

The telephone number of Liu Yang {#blank#}5{#/blank#}.

    On 19th September 1783, Pilatre De Rozier, a scientist, sent the first hot air balloon. The passengers were three animals and the balloon stayed in the air for about 15 minutes before hitting back to the ground.

    The first manned(载人的) flight was about 2 months later, with a balloon made by 2 French brothers. The balloon flew for a period of 20 minutes.

    Sailing through the sky in the balloon, high above buildings and trees, you can't feel or hear the wind because you're traveling in the same direction and at the same speed as it is.

    A hot air balloon has three main parts: the balloon, called an envelope; a basket, where passengers ride; and a burner system, which supplies the hot air.

    Most balloon envelopes are made of strong, lightweight nylon(尼龙). They are different in size and shape, but they have to be really, really big to lift even one person. Most weigh more than an adult man.

    The basket is usually made of wicker(柳条), which is strong but not too hard. It needs to bend a bit for a soft landing, just like a good jumper bends her legs instead of keeping them straight when she lands.

    The hot air balloon works on the theory that hot air rises faster than cooler air. When the burner system is turned on, it makes a noisy sound, but once the balloon is flying, the burner can be turned off. The air in the envelope will then cool, and the balloon will slowly go down unless the pilot starts the burner system again.

    To control a hot air balloon, a pilot adds hot air to it to go up or lets the air out to go down until he finds a wind blowing in the direction he wants to fly. But no matter which way the wind blows, the passengers have an amazing bird's-eye view of the world.

    Can dolphins talk? Maybe they can't talk with words, but they talk with sounds.

    Dolphins travel in a group. We call a group of fish a "school". They are not fish. Instead, they are mammals (哺乳动物), Dolphins talk to other dolphins in the school. They give information. They tell others when they are happy or sad or afraid. They say welcome when a dolphin comes back to school. They talk when they play.

    They make a few sounds above water. They make many more sounds under water. People can't hear these sounds because they are very high. Scientists make tapes of the sounds and study them.

要求：
（1）短文应包括提示中所有的写作要点，条理清楚，行文连贯，可适当发挥； 
（2）短文中不能出现真实的人名和地名； 
（3）词数不少于60，短文开头已给出，不计入总词数。

Dear Tom，

How are you？I'm Wang Tao. 

What about your family and your room？Please write to me soon. 

Yours，

Wang Tao