MSG(monosodium glutamate谷氨酸单钠) is a food additive(食品添加剂),which has been widely used by many food factories all over the world since it appeared first in Japan in 1909.

    MSG is a substance that is added to some food to improve its taste and color. It is used in foods around the world such as cakes, bread, frozen meat, fish and vegetables. In the beginning, people thought MSG was safe just like salt and sugar. However, in 1968 some people reported they seemed to have bad reactions(反应) to MSG after having had a meal at a restaurant. They included headaches and quick heartbeat . It was also reported that MSG excited a person's brain and caused his death in Japan. Scientists think that MSG may lead to many neurological disorders(神经紊乱). In mice studies done by a university, the result showed the mice didn't want to eat the food including MSG.

    Today many food companies “hide” MSG on food labels(标签) by using different names. If you see “natural flavorings (调味品) ”,“hydrolyzed protein” and  “spices” in a food label, you are probably seeing a hidden way to “report” MSG in a food label. Every time we have a meal in a restaurant, we always feel the food very delicious to taste, but sometimes it is dangerous for our health because some harmful food additives have been added to the food.

    To protect people's health, our governments, from central to local, are taking action to stop factories producing harmful food additives.

    There are all kinds of animals on our planet. Some are sweet, but some are not; some are small, and some are tall. Here are four pictures of some of the funniest, friendliest faces. But remember, although they look nice, it doesn't mean they are always friendly.

    Not all dogs are so cute, but most of them are pretty friendly. When you come near an unfamiliar(不熟悉的) dog, remember to hold out your hand, so he can smell you and see that you mean no harm.

    Cows love to eat grass, and they eat quite a lot! You needn't be afraid of this quiet farm animal. But don't run at a cow in a field or touch one, unless you are told by an adult it's okay.

    Horses are big, beautiful animals, but they can be easily angry. A horse might jump up if she hears a loud noise, or kick her legs if you come near too suddenly. All horses, like humans, are different.

    Chimpanzees(黑猩猩) make funny faces and put on a real show at the zoo, but believe it or not, they can be very dangerous. And they are strong too--much stronger than humans--so you should never make a chimp mad!

    On a rainy day, about 150 volunteers worked for eight hours to clean up Carson Creek that is near a river. About nine tons of trash(H l)was taken out from there.

    "We did a good job, "said Alan Specter, the organizer of the event, "Were planning to come back here one more time, three years from now, Of course, we hope that there won't be so much trash next time."

    The trash came in all shapes, sizes, and colors: bottles, bicycles, batteries, furniture, clothing, plastic bags, dolls, and even a golf bag with a full set of golf clubs(球杆).

    The dirty and tiring work was done by two volunteer groups Save the Bay and Watch the Whales. Most of the volunteers came from a local police station and a fire station. And some of them were old people who had already retired (退休)。

    That day, it rained a little. All of them wore boots, gloves and raincoats. The work took place along a two- mile river with over 500 big yellow trash bags every where.

    No one found anything that cost much. A five- year-old boy found an earring which he thought might be worth a million dollars. He said he'd sell it. Then he'd donate half of the money to Watch the Whales, and use the other half to buy his favorite ice- cream every day.

    Many people laughed at the boy's story. However, it was easily found that the environment there did become better.

    Now satellites(卫星)are helping to forecast(预报)the weather. They are in space and they can reach any part of the world.The satellites take pictures of the atmosphere(大气), because this is where the weather forms(形成). They send these pictures to the weather station. So meteorologists(气象专家)can see the weather of any part of the world. From the pictures, the scientists can often say how the weather will change.

    Today, nearly five hundred weather stations in sixty countries receive satellite pictures. When they receive new pictures, the meteor- ologists compare(比较)them with earlier ones. Perhaps they may find that the clouds have changed during the last few hours .This may mean the weather on the ground may soon change, too. In their next weather forecast, the meteorologists can say this.

    So the weather satellites are a great help to the meteorologists. Before satellites were invented, the scientists could forecast the weather for about 24 or 48 hours. Now they can make good forecasts for 3 or 5 days. Soon, perhaps , they may be able to forecast the weather for a week or more ahead(提前)