B

    Every day Tim gets up at five thirty and then goes to take a shower．After that，he makes breakfast for him and his wife (妻子)Betty．For breakfast．Tim has milk and bread and Betty has an egg and some salad．After breakfast，Tim goes to work．He is a train driver(列车司机)and he loves his job．

    Tim starts working at seven o'clock and drives trains on the London Underground．He usually works from Monday to Friday,but he sometimes works on weekends，too．At about one o'clock he has lunch．He eats sandwiches(三明治)．After lunch he works to four o'clock and then he goes home．

    In the evening Tim watches TV with Betty and plays games with his baby son，Ben．At ten he goes to bed．He usually reads books for haIf an hour in bed．He thinks reading is a good habit．

根据材料内容简要回答下列问题。

    One day, a mother crocodile (鳄鱼) and a baby crocodile swam slowly in a river. Suddenly, the mother crocodile saw a monkey, "Oh, a monkey! How nice if I have it for dinner!"

    "My son, can you go and get the monkey for me? I want to eat his heart (心脏)," the mother crocodile said.

    "All right," the baby crocodile answered.

    The baby crocodile swam near the river bank (岸). He shouted at the monkey, “Hey, monkey！Would you like some bananas? There are many banana trees on the other bank of the river"

    "I like them very much. But I can't swim. How can I get there?" the monkey asked.

    "Oh, I can take you there," the baby crocodile said.

    "Really? Thank you very much!" the monkey jumped onto the baby crocodile's back. In the middle of the river, the baby crocodile went into the water. When he came up again, the monkey was wet all over. "Don't do that again, or you'll kill (杀死) me!" the monkey shouted.

    "I know, but I must do that! My mother wants to eat your heart."

    "My heart? 你为什么不早点告诉我? I left it in a tree. We should go back for it!" So_ they went back.

    As soon as they got to the bank, the monkey picked up a big stone (石头) and climbed up onto the tree quickly. He shouted at the baby crocodile, "Don't you want my heart? Well, catch!" The monkey threw the big stone at the crocodile.

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.

    The Internet is shaping our lives. We already have online shopping services and mobile payment. However, this is just a start. The world's leading tech companies are planning to build smarter online communities. {#blank#}1{#/blank#} It was held in Wuzhen, Zhejiang last year. The development of artificial intelligence(AI,人工智能) was a hot topic at the conference(会议). If a machine can learn and solve problems as humans do, it can be called AI.

    The company Alibaba uses AI technology in its unmanned supermarket in Wuzhen. There is no salesperson in the supermarket, just an iPad on a desk that says "please smile". {#blank#}2{#/blank#} The bigger you smile, the more discounts(折扣) you get. Payment is done automatically through your Alipay account. When you first enter the supermarket, the supermarket's AI recognizes(辨认) your face and your account.

    There is also AI that can read lips. {#blank#}3{#/blank#} It recognizes your mouth's movements and turns them into voice or text messages. This could be very useful when you are trying to talk to someone on your phone in a noisy place. Police could also use the technology to help them find criminals by lip-reading recordings from video cameras.

    {#blank#}4{#/blank#} Microsoft's chatting robot XiaoIce can not only provide useful information, but also talk with people like a real friend. XiaoIce has a WeChat account(账户). After following the account, users can start talking with her. {#blank#}5{#/blank#} She keeps improving herself by talking with users.

    These technologies are being put into wider use. We may see a smarter world and better lives in the near future.

    In America, some teenagers are interested in charity. They are willing to help others. Some teenagers even set up their own charity group. Shreya Papneja is one of them.

    Shreya Papneja is 13 years old. She started a charity group called Children's Health Awareness Program in Schools. Her charity group helps kids make healthy choices and tries to stop childhood obesity(肥胖).

    A doctor once told Papneja that more than one-third of children were overweight. She did a lot of research about it. Then she made a website to teach other children about exercise and healthy eating.

    She does a lot of things for her charity group when she is free. For example, she often organizes different activities at schools around her hometown.

    I know how hard it is to make a change, but I won't give up. At least I've changed a lot. Now I eat more healthy food instead of junk food," she said to a reporter.