There are many kinds of animals that live in the forest, such as mice, rabbits, squirrels, bears.

    Animals in the forest depend on（依靠）one another for food. Many small forest animals, such as mice, eat green plants for food, and then larger animals eat them. This is called food chain. A food chain begins with the sun. The green plants in the forest use the sun's energy to make food for themselves. It's called photosynthesis(光合作用). Mice eat flowers and seeds that forest plants produce(生产).The mice get their energy from the plants, and the mice become food for a larger animal, such as the hunting hawk. So the energy from the sun passes from the plants to the mice to the hawk. A break（中断）in any part of this food chain means some animals may not have enough food to eat.

    Noise pollution is doing much harm to our health now. Noise，in fact，is unwanted sound and is a kind of invisible (无形的) killer. More and more students enjoy listening to music very much. When they listen to MP3 players, they like to turn up the volume (音量). Some people love listening to loud music. Furthermore, while watching TV, they keep the volume up. But they haven't realized that the noise is weakening their hearing. In fact, the noise not only influences each member in the family, but also makes a difference to the comfort of neighbors.

    Noise pollution is a source of increasing misery (痛苦) to people in our society. If people are often disturbed by it, they may feel uncomfortable or upset. What's worse, the noise can make people mad sometimes. If a worker works in a printing factory for too long, his/her hearing loss is much faster than a common person working in a quieter environment. So everybody must pay more attention to noise pollution. Generally speaking，the following four types of noise should be watched out for：

    Noise in the street

    Construction site (建筑工地) noise

    Noise at work

    Transportation noise

    I think the local department (部门) should take measures to control the noise levels, but it's everybody's duty to keep a quiet environment.

    What was discovered by accident? The answer is penicillin(青霉素). It kills germs. By killing germs, it saves lives. Suppose you are sick. You go to a doctor. She examines you. She says you have a "staph" infection(葡萄球菌感染). She gives you some medicine. You take it. The medicine knocks out the staph. Soon you are well. Before penicillin, this would not happen. Staph was almost sure death.

    Everyone wanted a medicine. Laboratories worked day and night. They grew the staph in small dishes. Then they tried to kill it. Nothing worked.

    The laboratory dishes had covers on them. They kept things from falling into dishes. Molds(霉菌)were a big worry. They are always in the air. You can't see them. They're too small .There are thousands of different molds. Molds can make an experiment (实验)fail. That's why dishes are covered.

    Dr. Alexander Fleming was working to kill the staph germ. He worked for years. One day he took a cover off a dish. He looked inside. There was a thick growth of staph germ. There was also some mold. Then he saw something strange. Where the mold was, there was no growth of staph. This is what Fleming probably thought. "By accident, I found a mold to kill the dreaded staph."

    This is how penicillin was found. But here's the real miracle(奇迹). There are thousands of kinds of molds. But only one kind can kill staph. The mold must have fallen into the dish a few days before. The cover was probably off only a few seconds(秒). In those few seconds the right mold fell into the right dish. Another mall might have thrown the dish away. But Fleming was very careful and smart. He understood what the mold did. How lucky the humans were!

    Have you ever wished that your life was like a reality TV show(真人秀节目)? Well, like it or not, things might be this way in the future.

    This is because of Google glasses. Glasses are the latest technology from Google. They have more exciting features(特征)than you could possibly imagine.

    For one thing, people who wear the glasses can shoot videos and record the sounds around them. So if your friend is wearing Google glasses, he or she can record your every move and broadcast live on the Internet for the world to see.

    There is a GPS system in the glasses. So if you get lost you can say" OK, Glass, where am I?", and it will find where you are and tell you where you need to 90.

    Google glasses are a bit like a helpful secretary. You can tell them what you want to write in an e—mail and they will type it for you.

    Since April 16, Google glasses have been on the market in small numbers. But by the end of the year anyone will be able to buy a pair for about 2, 500 yuan.

    Some people are not sure whether they find Google glasses cool or not. When someone is wearing Google glasses, it is not easy to see whether or not they are using them.