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.

    Training for a marathon requires careful preparation and steady, gradual increases in the length of the runs.{#blank#}1{#/blank#}, buy the best-fitting, best-built running shoes you can find. No one can say which brand will work best for you or feel best on your feet, so you have to rely on your experience and on the feel of each pair as you shop. When you have found shoes that seem right, walk in them for a few days to double-check the fit.{#blank#}2{#/blank#}.As always, you should stretch(伸展) at least ten minutes before each run to prevent injuries.

    During the first week, do not think about distance, but run five minutes longer each day.{#blank#}3{#/blank#}, it is wise to take a day off to rest. But during the next week, set a goal of at least a mile and a half per run.{#blank#}4{#/blank#} After two weeks, start timing yourself.{#blank#}5{#/blank#}.Depending on the kind of race you plan to enter, you can set up a timetable for the remaining weeks before the race.

A. For a good marathon runner

B. After six days

C. Before you begin your training

D. With each day, increase the distance by a half mile

E. Time spent for preparation raises the quality of training

F. If they still feel good, you can begin running in them

G. Now you are ready to figure out a goal of improving distance and time

    Food safety is a problem in all places around the world and people in different areas of the world prepare foods in different ways. The WHO released five simple rules for preparing food in a safe way.{#blank#}1{#/blank#}

    Key 1: Keep clean.

    The first key tells about the importance of washing. People should wash their hands often—before touching food, while they are preparing food, and any time after they go to the toilet. People should wash all surfaces and equipment used for preparing food.{#blank#}2{#/blank#}

    Key 2:{#blank#}3{#/blank#}

    People should separate raw, or uncooked food from foods that are already cooked and foods that will not be cooked. People should store raw meat, chicken, and fish in containers, or in separate areas. Raw foods should not touch prepared foods.

    Key 3: Cook completely.

    People should cook eggs and meat, like birds, seafood, and animals, especially carefully. These foods may carry more micro-organisms than other foods. Food like soup must be boiled for at least a minute to make it be cooked completely. It is also important that people re-heat cooked food completely.

    Key 4: Keep food at safe temperatures.

    When people are finished with eating, they should keep the left food in a refrigerator below 5℃ and shouldn't store it for too long. At room temperature, about 20℃, the amount of micro-organisms can increase very quickly.{#blank#}4{#/blank#}They cannot grow as quickly in a very hot or very cold environment.

    Key 5: Use safe water and raw materials.

    {#blank#}5{#/blank#} Damaged or old food may develop harmful chemicals as it gets older.

A. Eat cooked food immediately, while it is still hot.

B. They call these rules the “Five Keys to Safer Food.”

C. Separate raw and cooked.

D. People should use safe water and choose fresh foods.

E. Keeping everything clean helps people to avoid micro-organisms.

F. People should also protect cooking areas and food from insects and animals.

G. But temperatures above 60℃ or below 5℃ control the growth of micro-organisms.

    Ways to say “Happy birthday to me”

Tomorrow is my birthday, and I'm at an age when not everyone looks forward to cakes and presents.{#blank#}1{#/blank#} It always makes me feel excited to be alive and grateful for my life and my family. So I think even if your birthday is a regular old day at work or home, there are some easy ways to raise it to the special occasion.

    Give a gift to someone else.{#blank#}2{#/blank#} While everyone loves to open a birthday present, there is a lot of joy and goodness to be gained from being generous with others. Making a birthday donation (捐赠) to a charity that means something to you.{#blank#}3{#/blank#}Try something new. Today is new to us. Why not enjoy the newness of the moment? Dip your tones into some new waters, sign up for an adult education class, go for a new-to-you park or plan a new trip.{#blank#}4{#/blank#}.

    {#blank#}5{#/blank#} Whether or not you have the opportunity to share a meal, outing or party with friends and family, please take time on your birthday to connect with people who are important to your life, if you use social media like phones, you are likely filled with well—wishes from loved ones. Use these as a. jumping off point to start new conversations and reconnect with people who lift your spirits and support in your journey towards being your best self.

A. Connect with people who matter to you.

B. Freshen up yourself with countless opportunities.

C. It's better to give than to receive

D. This year my birthday is on a Saturday.

E. I love my birthday, though.

F. Download an app to learn a new language is also a good choice.

G. One choice is to donate a dollar amount to match your age.

How to stay focused in class

    Being relaxed during class is a bad habit, and it is also bad to your grade. Focusing in class not only proves to teachers that you are a capable student but also shows that you have the ability to control yourself, which will be very important.

    {#blank#}1{#/blank#} No matter how much you want to sit with your friends during the class, try your best to avoid them. Talking with friends around you is not going to give you the focus in class. This will get you into trouble.

    Look at teacher and make eye contact. Your teacher is not just standing up there talking.{#blank#}2{#/blank#} Show the teacher that he or she has your full attention by looking them in the eye. This person should have your full attention at all times during class.

Take notes. By taking notes, you'll be able to "get into" the lesson. Write down key points as your teacher speaks. And listen to the key phrases such as "This is important" "This is the main idea" "This will be the test" etc.{#blank#}3{#/blank#}

    Get involved in class discussions. This is a wonderful way to become a more focused, successful student. When a teacher asks a question, offer to answer it.{#blank#}4{#/blank#} This shows the teacher that you are listening carefully during the class.

    Ask a question.{#blank#}5{#/blank#} This really shows your teacher that you want to be better, and can recognize the things you are having difficulty with. Chances are that someone else in the class has the same question （and was too afraid to ask!）. They'll be relieved, and so will you.

A. Avoid sitting with friends.

B. This can help you listen more attentively.

C. If he or she ask for an opinion, share your own.

D. Talking with friends makes you lose interest in class.

E. He or she is trying to give you an acceptable education.

F. The more quickly you answer, the more attention you pay.

G. If you don't understand something, never be afraid to ask.

    Life can be a lonely thing without friends. Acquaintances (熟人) are easy to come by but true friends are a whole other story. {#blank#}1{#/blank#} Learn these four steps if you'd like to be a true friend that can be relied on.

    ●Be present for their highs and lows.

    If you're absent during my struggle, don't expect to be present during my success.

    （Will Smith）

    It's easy to be there for our friends when they ask us out for fun things. {#blank#}2{#/blank#} You might not feel comfortable while spending time with an emotionally weak person on the verge of tears, but true friends are always there when they're needed the most.

    ●{#blank#}3{#/blank#}

    When people talk, listen completely. Most people never listen.

    （Ernest Hemingway）

    Give your friends the gift of silence so they can drop their baggage and get on with living.

    ●Accept them as they are.

    Happiness can exist only in acceptance.

    （George Orwell）

    If you can't accept people as they are, you will never know the feeling of true friendship. {#blank#}4{#/blank#}

    ●Forgive the past.

    Holding onto anger is like drinking poison and expecting the other person to die.

    （Buddha）

    {#blank#}5{#/blank#} If so, you should understand that even the best of us suffer from the occasional slip of the tongue. Holding onto anger over a small mistake will make you look petty (小气的), so let it go.