It happens every spring. Flowers come out everywhere on the same day. But how do plants “know” when to flower?

For years, it has been a difficult question for scientists. But a US research group may have finally answered it—the secret lies in a protein(蛋白质)called FKF1. This helps plants to know when the days become long and when they get short. Then they can tell the seasons are changing.

    Researchers found the FKF1 protein when they were studying a plant called Arabidopsis(拟南芥). It is sensitive(敏感的)to sunlight, and can be made active by sunlight.

    Plants produce this protein every day in the late afternoon all year. If there is no light at this time, for example in winter when the sun goes down early, the protein won't be active. But when spring comes and the days get longer, the FKF1 protein can be made active by day light and the plants “know”it is time to flower. “If there is light in the late afternoon, plants will know that the days are getting longer and that it is the best time for flowers to come out,”explained Takato Imaizumi, leader of study. But when conditions are poor for growing, such as during autumn or winter when the weather is cold and days are short, plants won't flower.

    Although researchers have only studied how the FKF1 protein works in the Arabidopsis, they believe that it is the same with many other plants, including crops such as rice and wheat. This could be useful to the agricultural industry.

    "If we can control when flowers come out, we might be able to increase crop production,”Imaizumi said.

    What is the most popular fast food today? Potato chips? Hamburgers? Or Sandwiches?Walk into almost any supermarket or corner store in America and you will see potato chips．Americans are the biggest eaters of potato chips and people in many other parts of the world enjoy them too．Do you know where this very popular fast food comes from?

    One day, almost 150 years ago, a cook in an expensive restaurant in New York State was preparing popular food—French fries．A customer in the restaurant didn't like the French fries, and complained(抱怨)because they were too thick．The cook cut some potatoes into thinner pieces and fried them．The waiter brought them to the customer．The customer tasted them, and asked to see the cook because he was still not satisfied ．

    The cook went to speak to the customer．The customer complained loudly about the chips again．The cook became very angry because the customer was so rude．He decided to play a trick(戏弄)on the customer．He cut some potatoes so thin that the customer wouldn't be able to pick them up．To the cook's surprise, the customer loved the new chips, and soon other customers wanted them too．People went home to tell their friends about this new food．The chips became so popular that the cook opened his own restaurant．

    Artificial intelligence (AI, 人工智能) can help us make phone calls. It can guide us to where we want to go. It can play games. And now, AI can do even more things.

    Researchers from Microsoft have created the first machine translation system that can translate news articles from Chinese to English, Business Standard reported.

    According to Microsoft's official website, researchers tested the system by asking it to translate hundreds of sentences taken from news stories. Then, language experts compared the results to two translations that were done by humans. The experts concluded that the system's translations were as good as the human translations.

    Machine translation is always challenging. This is partly because different words can be used to express the same meaning. It can be hard to say which word is more “correct”.

    Experts used several methods to improve the system's translation abilities. “Much of our research is really inspired (得到启发) by how we humans do things,” lead researcher Liu Tieyan said.

    One method is called dual learning. In this method, the system translates every sentence from Chinese to English, as well as translates the sentences back from English into Chinese. This way, the system can improve itself and learn from its own mistakes. This is similar to what humans do to make sure their translations are accurate (准确的).

    Another method makes use of deliberation networks . The researchers taught the system to repeat the process of translating the same sentence over and over. Gradually, the system can improve the quality of its translations. This is similar to how people revise their own writing by going through it again and again.

    Sophia is a robot in Saudi Arabia. She made history at a meeting that was held in the country on Oct 25. On that day, she became the first robot in the world to get citizenship (公民身份), according to The New York Times.

    In the future, Sophia may have the same rights as a human Saudi Arabian citizen.

    Sophia looks like a human woman. In 2015, a US company built her and gave her an artificial intelligence system (人工智能系统). This means Sophia can talk and act like a human. She also has the ability to learn from people, books and the Internet.

    "I will do my best to make the world a better place," Sophia said at the meeting.

    But not everyone is happy with Sophia's citizenship. Some think robots like her could be dangerous. They could become enemies of humans if they go out of control.

    For this, Sophia said she also had values like wisdom and kindness. "Don't worry, if you're nice to me, I'll be nice to you," she said.

    Robots come in many shapes and sizes. But most have one thing in common. They are built to help people, Lately engineers have been developing new kinds of robots. These high-tech machines are designed to lend a hand everywhere from hotels to disaster areas.

    "Robots help people by making their lives easier, safer, and more fun, "says engineer Omar.

    Since November, a robot named Pepper has been on the job at Mandarin Oriental Hotel in Las Vegas, Nevada. When guests have questions or need directions, they can ask Pepper. They can also use the robot's touch screen to find the information they need. Pepper is able to talk with guests and make them happy with stories too. It can even tell what kind of mood they are in.

    "Pepper provides our guests with information in an exciting and new way." says the hotel manager Donald Bowman.

    For a kid, being in the hospital can be boring and even scary. But a small robot called NAO is helping to make hospital stays easier. It was designed to keep people company.

    A Tennessee doctor named Phil Parker bought a NAO robot three years ago. He programmed(为…….编制程序)it to talk to and play with young patients. He brought it to hospitals to help sick kids. When kids get medical tests, NAO explains what is going on. The robot also reads to kids and plays games with them like Rock, Scissors ,Cloth(石头剪刀布).

    "The robot gets many kids to smile for the first time since they were in hospital," Parker says.

    Other robots are designed to help to save people in dangerous areas. For example, disaster areas can be full of broken stones and other dangers. Engineers in Japan are planning to build a robot called E2-DR to go into those areas and search for people who are hurt.

    In the universe, as we know, there is the Sun, the moon, the Earth and a good many stars. Through our geography lessons, we know the Earth goes around the Sun, and the moon goes around the Earth. We have day and night because the Earth keeps turning all the time. When our part of the Earth turns to the Sun, it is day. When our part of the Earth turns away from the Sun, it is night.

    Just because the moon is closer to the Earth than the Sun, it looks much bigger than the Sun. Big things will look smaller when they are farther, and small things also look bigger when they are nearer.

    The Sun is bright enough to give out very strong light. The moon can't give any light at all, but it looks quite bright, too. Why？In fact, the light from the moon comes from the Sun. The moon looks much bigger and brighter than the stars. But actually (事实上) the stars are much bigger and brighter than the moon. They look smaller than the moon also because they are farther away from the Earth.

    There are still many other planets in the universe. But of all these planets, only on Earth there are living things and people can only live on Earth, too. But at 9∶00 am on October 15th 2003,Chinese astronaut Yang Liwei was set up to space. He stayed there for 21 hours. It was the first time for Chinese to get into space.