Diseases spread in many ways. An infected person can cough or sneeze on someone nearby, or they can spread germs through a handshake. But sometimes we pick up germs indirectly. A sick person might leave behind bacteria or viruses when they touch a door handle, for example. But what if those surfaces could clean themselves?
Two teenagers from Hong Kong asked themselves the same question. Now they’ve developed a door handle that can kill germs on contact. The idea is simple. Every time the door is opened, the movement creates power that starts a germ-killing reaction on the handle. In lab tests, their system killed about 99.8 percent of the germs that they spread onto lab dishes covered with their material.
Research by others has shown that door handles in public areas are often home to lots of bacteria and viruses, notes 17-year-old Sum Ming (Simon) Wong. He and schoolmate Kin Pong (Michael) Li, 18, wanted to design a covering for door handles that would kill germs. After doing some research, they learned that a mineral called titanium dioxide (二氧化钛) is known to kill bacteria. It’s already used in many products, from paints to desserts. To make their covering, the teenagers made the mineral into a very fine powder.
Titanium dioxide kills bacteria best when lit by ultraviolet (紫外线的) light, says Simon. UV light is found in sunlight. But UV light does not naturally shine on indoor handles or any used at night, so the teenagers light their door handle from within. To make sure the light reaches the coated surface, the teenagers made their door handle out of clear glass. Each end fits into a bracket (托架). Inside one of the brackets is a strong light-emitting diode (LED). From it comes UV light. And here’s the interesting and praisable part: The power that makes the UV light shine comes from opening and closing the door. The power from the door is then carried by wire to the LED inside the door handle.
The door handle system, Michael and Simon say, might cost no more than about $13 (about 81 yuan) to build.
【小题1】Why does the author mention the ways diseases spread at the beginning?| A．To explain how to kill bacteria or viruses effectively. |
| B．To demonstrate how most diseases are spread indirectly. |
| C．To remind readers of the importance of cleaning their hands. |
| D．To help to describe a new invention that prevents diseases from spreading. |
| A．It is too expensive for ordinary families. | B．It is powered by the movement. |
| C．It works better at night than daytime. | D．It is made of a metal absorbing UV light. |
| A．By producing titanium dioxide to kill bacteria. |
| B．By supplying enough power to the handle system. |
| C．By directing the UV light in sunlight to the coated surface. |
| D．By providing UV light to help titanium dioxide work better. |
| A．Cautious. | B．Critical. | C．Enthusiastic. | D．Disappointed. |
How To Exercise Your Brain
Just like your muscles- your brain needs exercise to keep it in good working order.
Learn something new. Keep your brain stimulated and active by picking up a new habit. Practising something new forms new neural（神经的）pathways in your brain.
Use your memory. It’s not as essential（必不可少的）to commit things to our brain as it once was, but the practice of remembering things can improve brain function.
Read every day. Reading a thrilling book can actually enhance your cognitive function. Reading also helps to develop language skills and increase attention spans.
| A．Stop multi-tasking. |
| B．Change your opinion. |
| C．The more you use your brain, the better it will work. |
| D．Repetition is one of the best ways to engage your memory. |
| E．Try to read a little bit every day to enjoy the brain benefits. |
| F．There are some good ways to make sure your brain stays healthy. |
| G．This will train your brain to think differently and more creatively about various situations. |
A good night’s sleep is one of the best things for your health. The following steps might help you enjoy a good sleep.
Create a nightly routine (惯例).
Learn your body clock.
Some experts believe sleepiness comes in cycles (周期性地). If you know the cycles in your body clock, you can use them to your advantage.
Paint your bedroom a relaxing color
First, take any unnecessary things away from your bedroom — they stand in the way of a good night’s sleep.
Choose the right pillow
One study found that neck pillows can actually improve the quality of your sleep as well as reduce neck pain.
| A．Hide your clock. |
| B．Change your habit |
| C．If sleepiness comes, get to bed in time. |
| D．You probably can’t fall asleep very easily |
| E．Then paint your room a relaxing color, like green. |
| F．The best neck pillow should be soft and not too high. |
| G．This is something you do every night before going to bed. |
Keeping cool in warm weather is a challenge. Risks of getting too hot in warm weather include a variety of heat-related illnesses. Keeping your body cool will also help to keep your mood calm too, for heat often causes feelings of stress and frustration. There are lots of simple and effective ways to stay cool in warm weather.
Don’t wait until you're thirsty to drink. Drink plenty of water before take part in any activities. Water is essential for keeping you cool during hot weather. Water should be drunk even if you don't feel thirsty.
Wear sunscreen. It’s best to limit your sun exposure between the hours of 10 a.m.and 4 p.m.each day during warmer months. When you are outside during these times, protect yourself well.
Wear lighter clothing. Lightweight, loose-fitting clothing will help to keep you cooler. If it is light in color, it’s even better, as this will reflect the heat and sunlight better.
| A．Stay out of the sun |
| B．Make food without using the stove |
| C．Besides, most of them are very affordable |
| D．Shorts and short-sleeved shirts are good choices |
| E．However, stay away from sugary drinks such as sodas |
| F．One shoe could be more comfortable or appropriate than another |
| G．While sunscreen doesn't have a cooling effect, its protective effect is vital |
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