We can express thoughts and feelings and send sounds and pictures on our smart phones today. We also communicate by using programs like Skype and Face Time. We can't send tastes, smells or touch, of course. But scientists in Britain are trying to develop a way for smart phones to do just that.

    Adrian David Cheok is a professor at City University in London. He wants people to experience communication using all of their senses. He said "In the real world, we can open up the glass, open the window. We can touch, we can taste, we can smell in the real world."

    To give users a sense of taste, researchers designed two electrodes (电极）that are placed on the tongue. A chemical process creates different tastes through molecules (微粒)on the surface of the tongue. This chemical process sends electrical signals that convince the brain that a person is tasting something. They have already created sour, salty, sweet and bitter tastes.

    "You put these two silver electrodes in your mouth, you put your tongue in between and then it stimulates electrically your tongue and you get a virtual taste perception in your brain."

    A device(设备）called "Scentee" permits users to have the sense of smell. Scentee plugs into a smart phone and can spray tiny clouds of fragrances, including flowers, fruits and coffee. Professor Cheok says the person speaking can activate the device.

    Scentee holds a container with about 100 different smells. The container must be replaced when all the scents（pleasant smells) run out.

    You can be proud of yourselves, even if you can only make one or two of these green changes. The goal here is to limit carbon dioxide and other greenhouse gases, which are closely connected to the big problem of global-warming (全球变暖).

    WAY 1: Bring your own cup to Starbucks. You'll get a 10-cent discount, and it's one less paper cup to end up in a dustbin. The store won't create more waste when they throw away a cup.

    WAY 2: Turn off your computer. When in standby mode, your PC is still using energy. Turning off a monitor (显示器) for 40 hours a week may only save $ 5 a month, but it reduces CO₂ by 750 pounds.

    WAY 3: Reuse plastic bags. Instead of throwing away 100 billion plastic bags a year, try and get a second, third, or tenth use out of them. Better yet, next time you shop, try a reusable bag. The amount of oil it would take to make just 14 plastic bags would run your car for one mile.

    WAY 4: Use recycled paper in the bathroom. Most of the toilet paper we use is made from trees found in forests. If every family replaced(替换)one roll of toilet paper with a recycled one, 424,000 trees would still be standing.

    WAY 5: Plant a tree. Adding green to your garden is beautiful and earth-pleasing. Just one tree will help make cleaner air and save the environment from 5, 000 pounds of hot carbon dioxide each year.

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    Saving the Earth shouldn't be so difficult，if we can do the following．

    First，we should take our time ． There is no need to hurry．We can walk or ride a bike to work．

    Second，we should smell the Each．Open the windows．Turn off the air-conditioner, and at the same time，save the energy．

    Third，we should enjoy cooking at home and having meals on our dinner table．So we can use our own bowls and chopsticks，not the plastic ones．

    Fourth，we should spend our weekends and holidays in the park playing games and just riding a bike around.

    Fifth，we should learn how to use old things well in the house，in the garden，or in the kitchen．

    Lastly, no one really has a mountain and a sea．Don't throw rubbish here and there．