Language students often think they have memory problems. They worry because they can't remember words. In fact, the problem usually isn't with their memory. The problem is with how they study.

    To remember words better, you need to understand how memory works. There are two kinds of memories: short-term and long-term. When you see, hear, or read something, it goes first into short-term memory. But short-term memory lasts for only a few seconds. You will only remember something longer if it goes into long-term memory. Your long-term memory is like a very big library with many, many books. And like a library, it's organized (有条理的). When you put away a book – or memory – you can't just leave it anywhere. You have to choose a place where you can find it again.

    How can you do this with vocabulary? The answer is to work with the word and think about the word in new ways. You can do this by writing new sentences that include it. Even better, you can invent a little story about the word, with people or places that you know. Another way is to make a picture in your mind with the word. For example, if the word is height, you can think of the tallest person you know and try to guess his or her height. All of these activities are good ways to think about words. They make the meaning of words stronger in your long-term memory. And they give a way to find a word when you need it.

    How do you light up the night sky? The answer is by using electricity. But did you know that nature can glow (发光), too?

    Scientists have found many glowing living things. Most of them live in the ocean. Some use their lights to talk to each other. Others use them to hunt, to mate (交配) or to protect themselves. The vampire squid (幽灵蛸), for example, uses a cloud of light to scare enemies.

    Scientists around the world are looking at this kind of light for new ideas. In 2013, the US company Gleaux said it has created the world's first light-producing plant, the Daily Mail reported. It is a genetically-modified (转基因的) plant. It can glow like a firefly.

    Alexander Krichevsky, the company's founder (创始人), and other scientists hope that in the future, glowing plants could replace lamps and glowing trees could light up highways. Krichevsky also hopes the technology could be used in farming. Farmers could know when their crops need water or are ready to be picked if they glow.

    While Gleaux is working on glowing plants, the French company Glowee is trying to use glowing bacteria (细菌) to light up shop windows and street signs. It's the same type of bacteria that cause a type of squid to light up, New Scientist Online reported.

    "Our goal is to change the way we produce and use light," said Glowee founder Sandra Rey. "We want to help reduce the 19 percent of electricity consumption (消耗量) that is used to produce light.

    Are you angry by the noise of your alarm clock every morning? Still feel sleepy after getting up? Now, you can say goodbye to that annoying alarm clock, you needn't hear its unpleasant noise every morning.

    The Glow pillow (发光枕)can wake you up with soft LED lights. The lights produce the brightness over 40 minutes just like the sunrise.

The pillow is taking the place of the traditional alarm clock. It was designed (设计)by Eosin McNally and Ian Walton to be against the pressures of a"24 hour "lifestyle.

    The pillow uses a kind of LED material below the surface. It wakes the user up with light. The material can also show the time on the pillow's surface, and it is perfect for those who sleep with their heads completely buried(埋)face down into the pillow. 40 minutes before the pre-set(预设)alarm time, the pillow begins to glow and gently brings the user out of sleep. The natural waking process helps to set "body clock" and makes people build a healthy sleep-and-wake habit slowly.