We live on the earth. We use the sea around us. What do we take from the ocean? And what do we give to it?

    We take fishes from the ocean—millions of kilograms of fish, every year, to feed millions of people. {#blank#}1{#/blank#}We take minerals (矿物) from the ocean. We can get salt by evaporating (蒸发) seawater. {#blank#}2{#/blank#}such as gold. {#blank#}3{#/blank#}Seaweed (海草) becomes food of many kinds—even candy and ice cream—as well as medicine. Believe it or not, fresh water is another gift from the sea. We can't drink ocean water. {#blank#}4{#/blank#}But ocean water becomes fresh water when the salts are removed. In the future, we will find ourselves depending more and more on fresh water from the sea.

    The sea gives us food, fertilizer, minerals, water and other gifts. What do we give the sea? We pollute the ocean all the time. {#blank#}5{#/blank#}Throwing waste into the ocean is killing off sea life. Yet as the world population grows, we may need the sea and its gifts more than ever.

    We are finally learning that if we destroy our sea, we might also destroy ourselves. Hopefully, it is not too late.

    English playwright Arthur Wing Pinero said, "Where there's tea, there's hope." Similarly, a Chinese saying goes that "Firewood, rice, cooking oil, salt, sauce, vinegar and tea are the seven necessities to begin a day."

    Tea is, without doubt, welcomed all over the world. According to Statista, a German website for statistics (数据), global tea production reached about 5.8 million tons in 2018. It has become the most consumed beverage (饮品) in the world – after water, of course.

    According to the UN, tea is much more than just a hot drink. It's a big part of many cultures around the world. You probably know that people in China use top-grade tea to show respect when receiving important guests. Meanwhile, the British tradition of afternoon tea is an important part of that country's identity. Making Malaysia's pulled tea has become a sort of art form, where drinkers take pride in its entertainment aspects.

    Apart from its cultural significance (意义), tea is also a medicine, used from ancient times to modern day. "Tea is cold and lowers the fire," Chinese Ming Dynasty herbalist Li Shizhen once said. The health benefits of tea are still being discovered today: preventing heart disease, obesity and cancer have all been linked to drinking green tea, according to the National Center for Biotechnology Information in the US.

    Hot or cold, bagged or loose-leaf, tea is more than a drink – it's a social custom and also a magic medicine, a link to the past and a way of life.

    Don't be too surprised if you see a car going down the road without a driver in Beijing these days. {#blank#}1{#/blank#}Last month, Baidu began to test its self-driving cars on open roads in Beijing.

    {#blank#}2{#/blank#}Since then, companies like Tesla, Uber and Baidu have been working to produce and test their own self—driving cars.

    Self-driving cars are safer than regular cars. {#blank#}3{#/blank#}They can remove the stress of driving and allow disabled or blind people to get around more easily.

    {#blank#}4{#/blank#}In one test, researchers pointed a laser pointer (激光棒) at the car's sensors (传感器) while it was moving. The car mistakenly thought that the laser beam was in its way and slowed down or changed the direction.

    The software that is used to direct the cars may not be safe enough. {#blank#}5{#/blank#}When we use our computers or smartphones, they sometimes crash (崩溃) without any reason. But if this happened to a self-driving car, the result could be deadly. Improvements to the software could be a solution to this problem.