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 “135520135.”

    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.

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

B. In any language, some letters are used more than others.

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

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

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

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

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

    With the summer holiday just around the corner, it seems like everybody is busy planning their vacations. Here are some tips that can help you enjoy your holiday without empting your pocket:

    Travel off-season

    Go to your desired destination while the demand is low and take advantage of huge discounts. During the peak season, the hotel and flight prices increase quickly, and you'll likely spend more of your vacation time standing in line due to the rush of tourists. {#blank#}1{#/blank#}

    {#blank#}2{#/blank#}

    Websites can help you find discount hotel rooms. Look for places that do not charge extra for children if they use the existing bedding. Stay with the locals. If you and your family are going to stay for a longer period, renting a small apartment is a good choice.

    Eat like a local

    Why eat at big chain restaurants when you can experience something new? {#blank#}3{#/blank#} During your family trip, try new food where the locals eat. This will not just save money, but also provide you with a new and different experience. For smaller meals and snacks, avoid restaurants and try street food or other takeout. 

    Don't hesitate to bargain

    Tourist- heavy places are known for overcharging for just about everything. Clothes, travel goodies, souvenirs, etc. are very expensive at these places. {#blank#}4{#/blank#} Bargain hard to get the best price.

    Choose local transportation

    {#blank#}5{#/blank#} Instead, take buses, railways or subways, which are always cheaper. If you are planning to stay for a while, you can consider renting a car. Hiring a car is much easier than carrying your bags everywhere if you are moving around a lot.

A. Save on hotels.

B. Surf the Internet while traveling.

C. Therefore, avoid buying anything there.

D. So it's best to find out when the off-season starts.

E. Planning your meals is another way to reduce your travel costs.

F. For this reason, you shouldn't feel ashamed to ask for bargains.

G .As a tourist, avoid taking taxis whenever possible, since they are expensive.

    Every living thing has genes. Genes carry information. {#blank#}1{#/blank#} They make sure that humans give birth to humans and cows give birth to cows. They also make sure that a dog doesn't give birth to a frog, or an elephant to a horse. However, genetic engineers take genes from one species-for example, a snake, and transfer them to another-for example, corn. {#blank#}2{#/blank#} Such new life forms have been described, by some scientists as a real-life Frankenstein(科幻怪人).

    Genetic engineers put duck genes into chicken to make the chickens bigger. They put hormones(激素) into cows to make them produce more milk. They put genes from flowers into beans and from fish into tomatoes. {#blank#}3{#/blank#} It just makes them easier and faster for the farmer to grow.

    The effects of genetic engineering on the natural world may be disastrous. The engineers may create strange life beings, or monsters. that we cannot control. {#blank#}4{#/blank#} They'll have to find one, fight for one-or kill for one. It may be your land they fight for-or you that they kill. Moreover, the effects of these experiments can often be cruel. In America, pigs were given human genes to make them bigger and less fatty. The experiment failed. The pigs became very ill and began to lose their eyesight. We would all like a better, healthier and longer life, and genetic engineering might give us this. On the other hand, it may be a dangerous experiment with nature. In the story of Frankenstein, the doctor created such a terrible and dangerous monster that he had to destroy it. {#blank#}5{#/blank#}

A. The information tells us what to do or what not to do

B. We must make sure that this tale remains a story-and no more than that

C. This doesn't make them cheaper, tastier, or healthier

D. The new life forms have no natural habitat or home

E. Then they feed the tomatoes to the fish

F. In this way a new life form is created

G. They are passed on from generation to generation

    I just realized that while children are dogs-loyal and affectionate-teenagers are cats.

    {#blank#}1{#/blank#} You feed it, train it, and boss it around. It puts its head on your knee and gazes at you as if you were a Rembrandt painting. It bounds indoors with enthusiasm when you call it. However, around age 13, your adoring little puppy(child) turns into a big old cat(teenager). Then when you tell it to come inside, it looks amazed, as if wondering who died. Instead of following your doorsteps, it disappears.{#blank#}2{#/blank#}

    Not realizing that the dog is now a cat, you think something must be desperately wrong within. Since you're the one who raised it, you assume that you did something wrong. Now you're dealing with a cat. Filled with guilt and fear, you redouble your efforts to make your pet behave. {#blank#}3{#/blank#} Call it, and it runs way. Tell it to sit, and it jumps on the counter.

    Instead of continuing to act like a dog owner, you can learn to behave like a cat owner. Put a dish of food near the door, and let it come to you.{#blank#}4{#/blank#}You sit still, and it will come, seeking that warm, comforting lap it has not entirely forgotten. Be there to open the door for it. One day your grown-up child will walk into the kitchen, give you a big kiss and say, "You've been working hard all day. Let me get those dishes for you."{#blank#}5{#/blank#}

A. It's so easy to be a dog owner.

B. Children as cats can turn to their parents.

C. You won't see it again until it gets hungry.

D. Then you'll realize your cat is a dog again.

E. Teenagers can understand and appreciate their parents' love.

F. But remember that a cat needs your help and your affection, too.

G. However, all the efforts made before now produce the opposite of the desired result.

    With busy schedules and limited hours of daylight, some runners find their only me to run is in the darkness of early morning or evening.{#blank#}1{#/blank#}. But if you have to run at night or in the early morning, make sure to follow these guidelines. Choose a Well-lit Route.

    It might not be your favourite route to run, but the most well-lit route is your first choice. {#blank#}2{#/blank#} and you'll always be able to see the road and avoid potential hazards.

    •Always Run Against Traffic

    It's easier to avoid cars if you can see them coming. Avoid busy roads and those with no shoulders or sidewalks.

    Run With a Friend

    {#blank#}3{#/blank#}. If possible, try to never run alone. If you're running alone, let someone know the route you're running and approximately how long you will be out.

    •Watch Out for Bikes and Runners

    Even if you're running on a path or in a park with no cars, always be aware of other runners and cyclists. {#blank#}4{#/blank#}. This advice applies to running in both daylight and darkness.

    •Put Away Your Music

    Make sure you leave your radio, MP3 player, or iPad at home. {#blank#}5{#/blank#}. You can't hear oncoming cars, cyclists yelling to move, dogs, or any other potential threat.

A. Oncoming cars see you better

B. There's strength and safety in numbers

C. Running in daylight is always a safer choice

D. A headlamp is also an essential item for runners

E. Before you stop or turn around, make sure your path is clear

F. Cutting off your sense of hearing leaves you at a disadvantage

G. Put your driver's license in your pocket or wear an ID tag on your shoe

This morning, I saw the shocking headline: "Passenger Dies When Car Crashes in Driverless Mode". In the article, various people said that the public should oppose the idea of developing driverless cars. They said that some advances in technology were unnecessary and could even be dangerous. Hence, we should cease accepting technology just because it is new. The newspaper reported that the car company had already apologised for the accident, but the families of the deceased（死者）said it was not enough. Nevertheless, the company still claimed that most people would be travelling in driverless cars one day soon.

On the one hand, there are many different groups of people around the world who live happily in the absence of new technology. Probably the most well known are the Amish（亚米希人）,a group of Christians living in rural America. They do not own or drive cars, watch TV, or use the Internet. They have lived mainly as farmers since the 18th century, and they will probably be living the same way in the distant future. They advocate a simple life with an emphasis on hard work, family, and community. They think that is better than caring about luxuries or following the lives of the rich and famous. It could even be argued that the Amish's quality of life is better since they live in and appreciate the natural environment rather than living in large, polluted cities.

On the other hand, new technology has provided people everywhere with many benefits over the years. For example, the latest weather-tracking computer programmes give people lots of warnings about potential natural disasters, which saves many lives. Moreover, the Internet has made it possible for friends and family to keep in touch easily even if they are on opposite sides of the world. It has also made finding opportunities in life much easier, as it allows people to make larger networks of friends through using social media.

Personally, I have benefited quite a lot from technological advances. I found my career as an AI designer through a social media network. My health monitor, which I wear all the time, has also helped me get into the best shape of my life. Of course, when new technology changes the way we live, it can be a scary prospect.

Nevertheless, I will always look on the positive side of change and accept it rather than resist it.