How much do you know about the bird world?

    Birds use three gaits: walking, running and hopping．

    In walking, the left and the right feet move in turn (轮流)．Each foot is on the ground for more than half the time, so there are more times when both feet are on the ground．In running, each foot is on the ground for less than half the time, and there are more times when both feet are off the ground．In hopping, the feet move almost at the same time．This means that for much of the time both feet are off the ground．

    Middle-sized and large birds walk at low speed and either run or hop at higher speed．Small birds, such as sparrows and swallows, usually do not walk, because walking may be too slow for them．It seems that the more time a bird spends in trees, the more likely it is to hop．Perhaps there is wide space in a tree between one thin branch (树枝) and the next, so walking is not a good choice, while on each small branch there is enough room to set both feet down side by side, so hopping seems to make sense．

    We use the Internet for many things: business, shopping, writing letters, talking to people, finding information and so on. In recent years, a new kind of English has grown on the Internet. There's no real word for it yet, so we'll call it e-talk.

    People don't like typing too much. To save time, they turn phrases into a few letters (called acronyms). Acronyms are often used in chat rooms(聊天室). Some of them are:

    BTW (by the way)                 BRB (be right back)

    LOL (laughing out loud)            IMO (in my opinion)

    People also use many abbreviations. They are shortened forms of words. Some common abbreviations are:

    info (information)                  puter (computer)

    pic (picture)                       sec (second)

    We usually don't see people when we communicate(交流) on the Net, so people have new ways to show feelings. Most people use their keyboards to draw "feelings", such as:

:-) (happy)    ;-)  (joking)   :-(  (sad)       :-O  (surprised)

    These days, many forums (论坛) have picture feelings. For example:

    There are even whole new words, like "newbies"(someone who is new on a chat board or forum). When you write something bad about someone else, it's called "flaming" the person.

    It takes time for people to get used to(适应) e-talk. Also, different groups on the Net have their own special ways of communicating. Newbies sometimes have to ask other people what they mean. As the Internet grows, e-talk will continue to grow and change.

Choose the best answer:

C

    Google and Toyota have worked together to create a new smart car. It can run on the road without a driver. It drives itself. The self-driving car hasn't been on sale to the public, so we don't know how much it costs. Another thing most people want to know is whether it will be safe enough to run on the road.

The self-driving car uses electricity (电) as its power, and it can't drive very quickly—the top speed would be 25 miles per hour. It is actually controlled by a computer system on the car. The system keeps on collecting information by some video cameras inside the car and a LIDAR sensor(激光达传器) on top of it. A computer processes the information and decides what to do. "The self'-driving car has only buttons (按钮) for go and stop, so it's very easy to use," an engineer of Google says. "And what's more, it will make car accidents fewer and make the world a safer place." The self-driving car has driven hundreds of thousands of miles in California, and it has only gotten into two accidents by human mistake.

    According to CNN, self-driving cars will also help to reduce the number of cars in big cities. "Self'-driving cars would be able to send you to the workplace and then pick up another person instead of stopping in a parking lot."

    American researchers have successfully developed a way to clean waste water without chemicals. The technique uses green plants. The tests were carried out at waste treatment centre. The scientists put plants in narrow containers inside a glass building. One end of each container was a little higher than the other end. Waste water was directed down the containers through the plants' thick roots as we expected. The roots absorbed the waste in the water and used it for food. At the same time the plants produced natural gas. The gas could be collected and sold as fuel(燃料).

    Four places in Florida are already using green plants to clean their waste water.

    When it comes to food, color rules! colorful fruits and vegetables are the key to a healthy diet. They give the body important things, such as vitamins and minerals, and help fight illness. Health experts(专家) think that kids should eat five or more servings (一份)of fruits and vegetables a day.

    Here are some rainbow colors to brighten your plate.

    Red

    Foods: cherries (樱桃), radishes (萝卜), red apples, strawberries, tomatoes

    ● Help to remember things well ● Good for the heart

    ●Reduce cancer risks(减少癌症风险)

    White

    Foods: onions, mushrooms, potatoes

    ● Good for the heart ●Reduce cancer risks

    Orange / Yellow

    Foods: apricots(杏), cantaloupes (甜瓜), carrots, corn, oranges

    ● Protect eyesight ●Build a strong immune system(免疫系统)

    ● Good for the heart

    Blue / Purple

    Foods: eggplants (茄子), plums (李子), purple grapes

    ●Reduce cancer risks ●Help to remember things well

    Green

    Foods: green beans, green peppers, lettuce(生菜), spinach(菠菜), peas

    ●Good for bones and teeth ●Reduce cancer risks ●Protect eyesight