Radar is an electronic device that detects planes, ships, coastlines, landmarks, and even storm clouds. The name radar comes from the first letters of the words radio direction and ranging. As the human eye uses light waves to see, radar “sees” with radio waves. Without radar, planes could not land safely in bad weather and ships could not move safely in thick fog{#blank#}1{#/blank#}

    In the 1800s it was discovered that radio waves could be reflected from objects. But scientists did not make great advances in radar research until the 1930s, when the world was threatened by war{#blank#}2{#/blank#} It has been used widely in almost every conflict since then.

    Echoes make it possible for radar to work. When a beam of radio waves is sent out, it strikes on an object and returns an echo. This echo is picked up by radar and recorded on a screen similar to television screen. On the screen an observer sees a flash, or a blip, that shows the direction and distance of the object.{#blank#}3{#/blank#}

    Airport control towers use radar to guide planes in for safe landings. Almost all large ships depend on radar to prevent collisions with icebergs or other ships{#blank#}4{#/blank#}Weather forecasters “see” the size, direction, and speed of storms on radar screens. Astronomers can even use radar to measure accurately the distance to the moon. Thus, the device has generated major advancements.

    {#blank#}5{#/blank#}Huge radar antennas have been installed all over the United States. They guard us against possible enemy attacks. We have ballistic—missiles (战略导弹)warning systems that can alert us to attacks when missiles are more than 1,000 miles away. Other radar systems warn us against enemy aircraft and even spying space satellites.

A. Police track speeders in radar-equipped cars.

B. These measurements are now highly accurate.

C. The device can be used in a wide range of fields.

D. It is therefore especially valuable to shippers and travelers.

E. During World War II many countries used radar effectively.

F. Today radar is used by commercial airliners and weather forecasters.

G. Strengthening national defense is one of radar's most important functions.

    Have you promised that you are going to get healthier? Maybe you want to lose weight, get stronger and have more energy. Maybe you are under the doctor's orders to eat right and take exercise more. {#blank#}1{#/blank#} But with so many choices, it can be hard to get started. So here are healthy tips that you can follow.

    Eat right. Healthy eating is harder than before. Now many supermarkets or restaurants are packed with unhealthy choices that cause weight gain and weaken energy. Over time, making poor food choices can cause illness. {#blank#}2{#/blank#} Eat natural and organic foods as often as possible. Cut out the junk food.

    Keep healthy. {#blank#}3{#/blank#} So take exercise at once. Once you get started, you will be more likely to stick to it. Reduce stress. In the US, 77% of people often experience physical stress. {#blank#}4{#/blank#} You can manage stress by taking exercise, getting enough rest and cleaning bad relationships from your life.

    {#blank#}5{#/blank#} Sure, some people are naturally happier than others. But there are things you can consciously do to be happier. And guess what they are all free. So if you want to be happier, there are a few things to do, for example, express thanks, help others, or how to meditate.

A. Sleep well.

B. Choose happiness.

C. Well, those all sound great.

D. But you don't have to be concerned about it.

E. That is not a group you want to be a part of.

F. So tell someone you love how you feel about them.

G. People who often take exercise are generally happier and healthier than people who don't.

    Gifts are fun because they are intended to be a physical expression of love for one's significant other. However, the acting of preparing a gift can be annoying, particularly if you are not sure what to choose. You can do anything from buying him or her something or panning out a romantic(浪漫的)day.

    {#blank#}1{#/blank#}

    Choose a suitable gift for your love.

    Romantic gifts are a symbolic gesture of your love while practical gifts are something with real value and use.{#blank#}2{#/blank#}Though you shouldn't be afraid to spend the extra money on a memorable gift, it's important to remember that there are more important things.{#blank#}3{#/blank#}The gift is meant to be a reflection of that. In some cases, it can feel even more thoughtful if you make something yourself.

    {#blank#}4{#/blank#}Although wrapping is sometimes seen as an unnecessary add-on, the time it takes to unwrap the gift makes the gift-giving more enjoyable for both you and your love. Presents are best if the other people don't know what it is yet.{#blank#}5{#/blank#}Besides, a romantic letter or card included in the gift also adds to the pleasure of the gift's receiver. More importantly, wait for a special moment to give the gift. You can present your gift at a point where the two of you are relaxed and things are pleasant. A gift - giving shouldn't be rushed at all.

A. Present it to your love.

B. Express your love to him or her.

C. The connection the two of you share is priceless.

D. Choosing a wonderful gift will help promote your friendship.

E. There's a certain pleasure in having something kept a surprise.

F. Your choice depends on the occasion, the relationship and his or her tastes.

G. Whatever you decide to do, make sure your gift appeals to him or her specially.

Rich and Famous

    Twenty years ago the most common ambition of American children was to be a teacher, followed by working in banking and finance, and then medicine. But today's situation is quite different. {#blank#}1{#/blank#} Instead they most commonly say they want to be a sports star, a pop star, or an actor—in other words, they hope to become a celebrity (名人).

    According to experts, young people desire these jobs largely because of the wealth and the fame. {#blank#}2{#/blank#} Let's take athletes and singers as an example. Their careers are short-lived. Many athletes' best time only lasts a few years and singers can have a very limited career. The field that was once the focus of their lives becomes something they have little or no involvement in. As a result, they'll have a feeling of worthlessness and a lack of control. {#blank#}3{#/blank#} The truth is quite simple: they have been so far removed from it for so long.

    In spite of these disadvantages, there is greater ambition than ever among young people to achieve that status. They are not satisfied just making a living—they want to be rich and famous. Globally, more and more TV shows provide talent competitions where winners can achieve their goals in just a few weeks or months. {#blank#}4{#/blank#}They unrealistically believe that this lifestyle is easily obtained and leads to great satisfaction.

    While many people argue that there is nothing wrong with having such ambitions, others feel that this trend will finally lead to dissatisfaction as more and more people are unable to reach their goals. {#blank#}5{#/blank#} That means they ignore the simple fact that great effort is needed before success. As a result, many people won't realize their childhood dreams, which could have a negative effect on their happiness.

A. The younger generation don't favor these professions any more.

B. In many ways this has been brought about by the celebrity culture.

C. Unfortunately, they do not always have a positive effect on people's life.

D. Besides, it can be difficult for them to adapt back to a normal everyday life.

E. People no longer have a sense of satisfaction once their goals have been achieved.

F. This quick way of gaining wealth and fame creates a celebrity culture among people.

G. The reason is that they don't realize it takes talent and hard work to be rich and famous.

    Your children are watching you. {#blank#}1{#/blank#} According to the Health Program, developing healthy habits is an important part for your children. And when it comes to developing healthy habits, parents influence their children more than anyone else.

    {#blank#}2{#/blank#} What happens during those early years can influence children for the rest of their lives. Children watch what others do carefully and imitate the behaviors of those closest to them. Most of the time, "closest" means their parents and the advice "do as I say, not as I do" from parents is not good for children. As parents, you should do the following:

    {#blank#}3{#/blank#} If you do that, your children are more likely to be enthusiastic about developing theirs.

    Let your children see you taking care of your own physical health by eating fruits and vegetables, and exercising on a regular basis. Talk to them about healthy habits in age-appropriate terms and at a proper time. {#blank#}4{#/blank#} When it comes to encouraging physical activities, show them that running, jumping, walking and swimming can be fun for grown-ups too.

    {#blank#}5{#/blank#} Computers, televisions and other forms of technology are a major part of life in the 21st century. Unfortunately, as the use of technology in the home increases, so does the time spent watching TV or playing on the computer. So as parents, you should also arrange the time for your children wisely.

A. Use technology wisely.

B. Take part in physical activities and exercise regularly.

C. Be enthusiastic about developing healthy habits of your own.

D. Children prefer to imitate their parents rather than talk to them.

E. Your actions are speaking to them louder than your words will.

F. This can be helpful in teaching your children to form physical habits.

G. It's easy for the children to form their healthy habits when they are young.

    Think positive

    How are you feeling today? If your head's in a spin because you've had a bad night's sleep, or maybe you've just got too much to do, the chances are you're not in the best of moods. If everything seems like an effort and you have a negative attitude, the last thing you want to be told is to be positive! {#blank#}1{#/blank#}

    Of course, developing a positive attitude is easier said than done. {#blank#}2{#/blank#} When you're feeling down, it is hard to be optimistic. But a study in the US has found that people who are optimists are more likely to live longer than those who have a more negative approach to life. So, maybe the thought of a longer life might encourage you to have a more hopeful outlook on life.

    {#blank#}3{#/blank#} Professor Lewina Lee from Boston University School of Medicine, who worked on the study, told the BBC that: "Our findings speak to the possibility that raising levels of optimism may promote longevity and healthy ageing." And she advises that pessimists could benefit from doing things like imagining a future where everything turns out well.

    {#blank#}4{#/blank#} Vicki Siska says "Music feeds my soul. A sense of humour keeps things in perspective." And Pippa Kennedy says" being grateful for what you have — and lots of chocolate —helps!" {#blank#}5{#/blank#} That's probably why other people have recommended doing yoga as well as staying fit and healthy to help maintain a positive outlook on life.

A. It doesn't come naturally to everyone.

B. As we know, every coin has two sides.

C. But being positive could have more benefits than you think.

D. Pessimists tend to give up when facing difficulties.

E. The saying goes that a healthy body leads a healthy mind.

F. People have been giving their personal advice on keeping a positive approach to life.

G. The study concluded that optimists may find it easier to control emotions and get less stressed.