Happiness means different things to different people. For Mary, who has {#blank#}1{#/blank#} severe sleeping problem, happiness is as simple as having a good night's sleep.

    Bed was once a place {#blank#}2{#/blank#} Mary went to rest after a long, hard day. {#blank#}3{#/blank#}, she has not had a full night's sleep in almost six months. Her doctor said that {#blank#}4{#/blank#} (count) sheep might help her fall asleep. She tried this, but soon got tired of it after it failed to work. She finds the nights without sleep almost {#blank#}5{#/blank#} (bear) . She is always sleepy and lacks energy during the day.

    Mary is not alone. Studies show that more than one in three people worldwide struggle with getting enough sleep. It often takes on different {#blank#}6{#/blank#} (form) : some people can get to sleep, but wake up much too early; some get a full night's sleep, but are {#blank#}7{#/blank#} (disappoint)  to find that they still feel tired when they wake up; others, like Mary, find {#blank#}8{#/blank#} difficult to fall asleep in the first place.

    Specialists say that people should not worry too much about this problem. In most cases , a lack of sleep {#blank#}9{#/blank#} (cause) by anxiety and pressure. It is important to keep yourself {#blank#}10{#/blank#} good spirits and to be positive. 

    In 1940, four teenage boys and their dog were walking through woodland close to Lascaux, when their dog suddenly disappeared. The boys searched all around. They came to a cave and looked into the cave{#blank#}1{#/blank#} could see nothing.

    A few days later, the boys returned to the cave. They could hardly believe {#blank#}2{#/blank#}eyes. In the weak lamplight, the boys saw red horses and cows, and black bulls and deer charging across the walls of the cave, which looked so {#blank#}3{#/blank#}(frighten) that the boys jumped back in fear. Little did the boys know that they had made one of the most important{#blank#}4{#/blank#}(discover) of that century.

    The Famous Lascaux Caves consist of a large hole and{#blank#}5{#/blank#} series of connecting caves, with a natural water system. The paintings there were an especially important find because they are so numerous and so well preserved. After a few years, the caves were opened{#blank#}6{#/blank#} a tourist attraction, and 1,200 people per day came to the site{#blank#}7{#/blank#}(admire) the paintings{#blank#}8{#/blank#} (fortunate), many visitors resulted in changes in the cave's atmosphere, and green algae (水藻) began to grow around the walls. Since then, the caves {#blank#}9{#/blank#}(close) to the public in an effort to conserve the fragile paintings in this precious underground site.

    Today, the caves have computer-controlled air-conditioning and are inspected daily. Scientists hope that these precautions will prevent any{#blank#}10{#/blank#}(far) damage to the paintings.

    When Joe was about to start school, all signs pointed to success. Yet things turned out  {#blank#}1{#/blank#}(be) quite disappointing. The fourth grade even found him at the bottom of the class. Joe struggled day and night, but  {#blank#}2{#/blank#}made him upset was that it did not work—until one stormy afternoon.

    On that afternoon, the math teacher was introducing difficult concepts  {#blank#}3{#/blank#}dark clouds covered the sky, and the storm set in. Although she tried to make the kids concentrate, the thunder won the battle for their attention. No one grasped the concepts. Except for Joe. He understood{#blank#}4{#/blank#} and answered all the questions correctly. The teacher patted him on the back and told him to go around to the others and explain how he had managed it. {#blank#}5{#/blank#}(encourage) by his newfound success, Joe moved quickly throughout the room. Soon math time  {#blank#}6{#/blank#}(follow) by the time for art. All children  {#blank#}7{#/blank#}(natural) drew dark pictures on such a day. Except for Joe.

    Since then, Joe started to work even  {#blank#}8{#/blank#}(hard) than before. His math teacher was always curious about the  {#blank#}9{#/blank#}(amaze) change: Why had that stormy day changed Joe?

    At the graduation ceremony, Joe presented the teacher with his most familiar  {#blank#}10{#/blank#}(possess) — the picture of bright yellow sun. On the picture Joe had written: This is the day I woke up to my brightness.

    On May 18, it was announced that China had achieved success in drilling fire ice, a frozen {#blank#}1{#/blank#}(mix) of water and natural gas, from the South China Sea. {#blank#}2{#/blank#}(official) known as methane hydrates(甲烷水合物), fire ice produces a high amount of energy when {#blank#}3{#/blank#}(burn) and its chemical reaction produces nothing but dioxide and water.

    Fire ice, both clean and energy-intensive, {#blank#}4{#/blank#}(consider) the fuel of the future. Many countries, including the United States and Japan, have long been conducting research on fire ice, but extracting（提取）it from the bottom of the sea has been a common problem {#blank#}5{#/blank#}(trouble) all of them. But, the Chinese team succeeded in drilling fire ice for nearly eight successive days, {#blank#}6{#/blank#}is a big breakthrough.

    However, it is too early {#blank#}7{#/blank#}(say) a new energy source has been found. The world's total fire ice reserve is about 21,000 trillion cubic meters, which, if extracted, could meet the world's energy need

    {#blank#}8{#/blank#}1,000 years. But the successful test drilling of fire ice does not mean it can be extracted for {#blank#}9{#/blank#}(industry) use. China has to solve many problems before it can use fire ice as a source of energy.

    It's thought that only by 2025 at{#blank#}10{#/blank#} earliest might people be able to look at realistic commercial options.

    China successfully landed the Chang'e 4 lunar probe(月球探测器)on the far side of the moon on January 3,2019, becoming the only country in history{#blank#}1{#/blank#}(touch) the lunar surface unseen by those on Earth. The far side of the moon has been seen and mapped{#blank#}2{#/blank#}(previous) by astronauts of the Apollo missions. But it is the first time that the moon's far side{#blank#}3{#/blank#}(set) foot on by any spacecraft, and the successful landing of Chang'e 4 is seen as a major milestone in space {#blank#}4{#/blank#}(explore).

    The Chang'e 4 spacecraft consists{#blank#}5{#/blank#}two parts:a lander and a rover(巡视器). Representing China's{#blank#}6{#/blank#}(new) step in the lunar probe project of all time, it landed at 10:26 am Beijing time. Then it sent back a photo of the landing place.{#blank#}7{#/blank#}(shoot) through cameras on the probe's lander, the photo marks the world's first image taken on the surface of the far side of the moon. One of the photos published by the China National Space Administration shows the place{#blank#}8{#/blank#}Chang'e 4's rover-named Yutu 2~will be heading hours later for{#blank#}9{#/blank#}purpose of conducting further research. The name Chang'e has its roots in the Chinese goddess of the moon. In the ancient tale, Chang'e{#blank#}10{#/blank#}(fly) to the heavens and landed on the moon as her final resting place.

    A hotel chain is employing human bed warmers to help guests get a good night's sleep. {#blank#}1{#/blank#} (dress) in special all-in-one sleeping suits, the walking electric blankets are sent to warm the beds of guests staying at the Holiday Inn {#blank#}2{#/blank#} they get under the covers.

    Dr Chris Idzikowski, {#blank#}3{#/blank#} (direct) of the Edinburgh Sleep Centre, said the idea could help people get off to sleep. He {#blank#}4{#/blank#} (explain) that "There's plenty of scientific evidence to show that sleep starts at the beginning of the night {#blank#}5{#/blank#} body temperature starts to drop. The drop occurs partly because the blood vessels (血管) {#blank#}6{#/blank#} the hands, face and feet open up and release heat." "A warm bed –approximately 20 to 24 degrees Celsuis –is {#blank#}7{#/blank#} good way to start this process while a cold bed isn't. It helps people sleep well especially as it's taking much {#blank#}8{#/blank#} (long) for them to warm up when they come in from the snow."

    Dr Chris Idzikowski and {#blank#}9{#/blank#} (he) colleague Jane Bednall said the idea was like "having a giant hot water bottle in your bed". The five-minute free bed warming sessions will be tried out in London and Manchester {#blank#}10{#/blank#} the end of next month.