根据短文内容，从短文后的选项中选出能填入空白处的最佳选项，选项中有两项为多余选项。

      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 threemain 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 20 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. {#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.

{#blank#}1{#/blank#}

    Safety in the highway is not totally out of our hands. Here are four ways we can protect ourselves when we travel.

    {#blank#}2{#/blank#} people in small cars are injured more often and more severely than people traveling in large cars. Factories of small cars are strengthening their products' safety, which helps. But the mix of large cars and small cars on the road is the main reason of the problem.

    Being thrown into glass and mental cars parts, or being thrown from the car can really hurt or even kill you.

    {#blank#}3{#/blank#}The safety belt's main purpose is to pull you back if your car has a sudden crash with another vehicle or object, or if it rolls over. A belt can reduce the chance of deadly injury by 45% and the chance of serious injury by 50%.

    Air bags are important. More than half of all new cars sold have air bags. Air bags provide protection in frontal crashes—the type of crash that kills the most drivers—when they are also wearing safety belts. Most people are demanding air bags in the cars they buy.  {#blank#}4{#/blank#} Effective as they are, they can't take the place of safety belts.

    Drunk driving crashes are less likely to happen if you don't drink. {#blank#}5{#/blank#}Many people have realised that drunk driving can lead to death and injury, prison time and other results. There are movements to strengthen penalties(处罚) for drinking and driving.

A. How to drive safely?

B. You are safer in a large car

C. How to protect ourselves in the highway?

D. Air bags are not installed in all cars.

E. That's why safety belts should be worn.

F. Drunk driving is the most serious problem.

G. But the protection provided by air bags is limited in side or rear crashes.

    Nowadays a vegetarian (素食的) lifestyle is becoming more and more popular. Keeping a vegetarian diet is one of the best things we can do.

    {#blank#}1{#/blank#} A well planned vegetarian diet provides us with all the nutrients (营养素) we need and avoids fat, cholesterol (胆固醇) found in animal flesh, eggs, and dairy foods. And it can provide protection against various kinds of diseases, including the three biggest killers: heart disease, cancer, and other serious diseases. The American Dietetic Association states that vegetarians have lower rates of death from heart disease, lower blood cholesterol levels, lower blood pressure and lower rates of high blood pressure. {#blank#}2{#/blank#} Scientists have also found that vegetarians have stronger immune systems than their meat-eating friends. {#blank#}3{#/blank#} Vegetarians live, on average, 6 to 10 years longer than meat eaters.

    {#blank#}4{#/blank#} Animals raised for food consume the vast majority of their calories simply in order to live, just as we do. We feed more than 70 percent of the grains to farm animals. So it's really a huge waste, isn't it? Try your best to find tips on the health benefits of a vegetarian diet. {#blank#}5{#/blank#}

A. Growing all the crops needed to feed animals requires great amounts of water and land.

B. This means that they are less likely to be affected by everyday illnesses like the flu.

C. Vegetarian diets are the only diets that work for long term weight loss.

D. All of these diseases are more likely to happen to meat eaters.

E. Healthy vegetarian diets support a lifetime of good health.

F. It's never too late to turn over a new page.

G. Living on plants also saves energy.

There is no doubt that the first day of school can be crazy for most of students. New kids wander (徘) around in circles, waiting for the opening of the school door. The school nurse needs your medical records. {#blank#}1{#/blank#} The freshmen are running in all directions, looking for their new classrooms.

    How can you overcome the first-day chaos? If you will go to a new school, try to arrange a visit before classes begin. Explore any areas, such as the playground, library, or school labs.{#blank#}2{#/blank#}

    Get one and read it before your school, starts-then keep it in your school bag until you're familiar with your new surroundings. Your first day is also the time to bring in school supplies and books.

    You should arrange your schoolbag well the night before you go to school so that you won't look for what you need at the last minute.

Did you try on eight different coats before deciding on what to wear?{#blank#}3{#/blank#} The best choice is to wear what makes you feel good, whether it is a new coat or an old sweater. If you plan to wear a pair of shoes, make sure they fit you well.

    {#blank#}4{#/blank#} Some start with a gathering, while others may jump right into the first-period class. You'll meet your new teachers, and they will probably give you an overview of the courses, class rules, what the semester will be like, what supplies you'll need, and expectations of your performance and behavior. Some teachers will jump into their first lesson, while others may have some activities.{#blank#}5{#/blank#}

A. Some schools even offer maps.

B. But you forget to bring it with you.

C. It all depends on the class and teacher.

D. Don't depend on your parents any more.

E. Each school has different opening-days.

F. You can also try to ask the teachers for help.

G. Lots of students have difficulty deciding on what to wear on the first day of school.

    Swim-with-dolphins

    Humans have always been fascinated by dolphins and there has been a long history of association between the two.{#blank#}1{#/blank#}. The “swim-with-dolphins” tourist industry is becoming more popular every year. The chance to see dolphins in the wild is often a lifetime dream for many people and tour operators are always on the lookout to give their tourist swimmers the best experience they can. After all, it can cost a large amount of money to have this kind of holiday experience. {#blank#}2{#/blank#}

    Research has shown that while dolphins can move away if they do not want to interact with human swimmers, they do not like it at all if the swimmers slip into the water directly on top of them or if humans are in their path of travel. However, if swimmers enter the water to one side of them, the dolphins do not avoid the swimmers to the same extent.{#blank#}3{#/blank#}

    In all cases, the dolphins seem to have become more sensitive to the presence of the swimmers. For dolphins, swimming with humans is not necessarily a high priority(优先权). {#blank#}4{#/blank#} It is a new and unusual experience for them.

    {#blank#}5{#/blank#}The advice is that dolphins should be given adequate periods of time throughout the day when they are not exposed to tourism. Humans' lifelong dreams of swimming with dolphins in the wild have severely affected them, leaving not enough time for them to rest and take care of their own babies.

    If we are to enjoy these remarkable animals and not just use them for our entertainment, then we must carefully monitor the “swim-with-dolphins” industry worldwide.

A. They cannot fulfill their lifelong dreams.

B. This possibly seems like less threatening behavior to them.

C. In the long term there could be harmful effects on the dolphin's well-being.

D. It is frequently asked whether “swim-with-dolphins” tourism should be stopped.

E. So tour operators try to place eager swimmers as near as possible to the dolphins.

F. Over time this has turned into a worldwide tourist activity--swimming with dolphins.

G. In fact, only some baby dolphins will be relatively willing to participate in the interaction.

    Do you enjoy your work? Maybe you do or maybe you don't. Chances are that you fall somewhere in the middle: you have good days and bad days, and you could definitely be happier than you currently are.{#blank#}1{#/blank#}.

    Be Friendly to Your Colleagues

    In some big offices, people might not even say "good morning" to one another. {#blank#}2{#/blank#}. You might think that you have nothing in common with them, but if you strike up a conversation, you may well find that they share some of your interests, hopes or ambitions.

    Focus on How You're Helping Clients

    Some jobs are pretty tiresome — there's no way round that. Whatever you're doing, though, you're helping someone.

    Perhaps you work in McDonalds, helping customers who want a cheap, quick meal. Perhaps you do data entry, helping a big company to get their records organized so that they can take better care of their clients. In most jobs, you've got the potential to make someone else's day that bit better.{#blank#}3{#/blank#}.

    Do Your Hardest Task First

    Have you ever put off a difficult phone call or a high­pressure task for days and days, only to find it appears larger and larger in your mind? I've read a lot of productivity advice over the past few years, and something that almost all experts seem to agree on is that it's a good idea to get tough tasks out of the way as quickly as possible.{#blank#}4{#/blank#}. Plus, you'll constantly have that task hanging over you and dragging your mood down.

    {#blank#}5{#/blank#}

    Try eating at regular intervals — and go for healthy, tasty foods which make you feel energized rather than sluggish. Fresh fruit is a great snack option, or you can have dried fruit, nuts and/or seeds. Don't forget to drink enough water, too.

    These are all little, but significant, ways to be happier at work today. Put them into practice and you will feel inspired!

A.Eat Sensibly and Regularly

B.Eat Outside during Your Lunch Break

C.Here are several ways to be happier at work

D.The longer you wait, the more resistant you will feel

E.Doing that will almost certainly put a smile on your face

F.It costs nothing to be polite and friendly to your colleagues

G.Look for some small items to bring a bit of happiness into your day