The world is in danger. At one time there were 1,300 different plants, trees and flowers in Holland, but now only 860 remain(剩余). The others have been destroyed(破坏) by man. We are changing the earth, the air, the water and everything that grows and lives. We can't live without these things. If we continue doing like this, we will destroy ourselves.

    What will happen in the future? Perhaps it is more important to ask "What must we do now?" The people who will be living in the world of tomorrow are the young of today. A lot of them know that conservation(对自然环境的保护) is necessary. Many are helping to save our world. They plant trees and protect animals in forest. In a small town in the United States, a large group of volunteers cleaned the banks of their rivers. Young people may hear about conservation through a record called No One's Going to Change Our World. It was made by the Beatles, Cliff Richard and other singers. The money from it will help to protect wild animals.

    Giraffes are beautiful, smart and friendly. They have long legs and necks (脖子). They are so tall that they can grow up over 5 meters (米). So how do they sleep or drink?

    You may think it's difficult for them to sleep, but they have no such problems because giraffes don't often stop for a sleep. Giraffes just need to sleep about thirty minutes a day. When they sleep, they don't always lie down (躺下). They usually sleep for minutes at a time, because it's difficult for them to get up again. And it's a great danger to sleep in the wild (荒野). But the giraffes in the zoo sleep for about 4-6 hours every day. They usually lie down when they sleep.

    Drinking water is a big problem for giraffes because their long necks are too "short". To drink water, they must spread (伸展) their front legs in a difficult way. And in this way, other animals like Africa's big cats can easily hunt (猎食) them. So they usually get most of their water from the trees and flowers. Giraffes don't need to drink water very often. They can even drink no water for months!

A tornado (龙卷风) is a kind of strong storm with air which moves in a circle quickly. They can move over 200 miles per hour and cause a lot of damage (损坏). As they move across the land, they can easily pick up cars, trucks, and even houses, and then throw them very far. It is important to find a safe place if a tornado gets close.

A safe place could be a basement ( 地下室) or the lowest floor. If you are in a home without a basement, try to find a first-floor bathroom or a small room without windows in the middle of your house. You should curl up (蜷缩) into a ball and cover your head and neck with your hands.

But there are some people who actually want to get close to tornadoes. They are scientists who want to learn more about tornadoes. One of the best ways to do this is to get as close as possible to the tornado. They use special tools to measure (测量) what is happening in and around a tornado.

One special tool is called a tornado probe ( 探测仪). Inside the tornado probe, there are sensors (传感器) to measure wind speed, temperature, pressure, and direction.

Some probes even have cameras, so the scientists can see and understand what it's like to be in a tornado.

To be able to get these measurements, the scientists have to get a tornado probe near or into a tornado. Scientists will try to guess where a tornado will go next. Then they drive to that location and put down the probe. If they do not guess correctly, they pick up their probe and try another place. If they are right, the tornado will go near or even right over the probe. Then they take all of the measurements

from the probe and use them to predict where future tornadoes may form (形成) and travel. And they can give people some warning to keep away from a dangerous tornado.

After a relaxing weekend, children have to go back to school on Mondays. For parents, they should do something helpful (有帮助的) to let their children get to school on time.

Let children take a good shower. It's good for children to take a shower before they go to bed. It can not only help them sleep well but also save time next morning.

Ask children to go to bed early. School starts at 8：00 a.m. So please let your children go to bed before 9：30 p.m. Your children should (应该) sleep for about nine hours every day. This is quite important because they have to get up early next day.

Make a good breakfast for children. Breakfast can help children study better (更好的) in the day. It can help students listen to teachers carefully (细致地) and think well in class. Also, it's good for their health.

Getting to school on time is very important for your children. So please help them. If you can do the things above (以上), they will study and live happily.

What did people do to communicate in ancient times? Here are some very interesting answers to this question.

Alphorns（阿尔卑斯长号角） were once used to communicate in the mountains in Switzerland. They are very long and they are very heavy, too. So, alphorns are hard work to blow. Then why use them? Well, they make a loud sound which travels much further than the human voice. Herdsmen（牧民） used them to call cows in the distance for milking. At sunset, alphorns were also used to send a message down to villagers that all was well. These days, they're mostly used as musical instruments.

The people of La Gomera, an island in Europe, have their own special way of sending messages from mountain to mountain. They use a whistled（口哨） language called el silbo, which comes from their language Spanish. Whistling can be heard within five kilorneters, which means it can be used across much greater distances than shouting. El silbo can be used for all kinds of messages, including greetings and announcements. El silbo is used a lot less than it used to be, but primary school students in La Gomera have to leave it.

Did you know it 's also possible to send messages without making a noise? This is called visual communication, and it includes the use of flags and even smoke. Long ago, soldiers along the Great Wall of China used smoke as a warning. If they noticed the enemy from their signal（信号） tower, they lit a smoky fire. When soldiers in other towers saw the smoke signal, they lit fires, too. In this way, messages about the enemy's arrival could travel as far as 800 km in just a few hours.

① Do you have a dog? What can your dog do for you? Do you know that dogs can read our feelings? Now some people find that dogs can smell (v.闻到; n.嗅觉) people's stress (压力).

②Dogs really are man's best friends. They have special smell. A new study said that dogs can smell if people are feeling stressed. Teachers at Queen's University, UK, made the study. They got breath(呼吸)and sweat(汗) from people both before and after doing a hard maths problem. They looked at the people's heart rate (心率), blood pressure (血压) and stress feeling in the study. Dogs can smell the difference in breath and sweat from people. Then they can know when people are stressed.

③The finding is wonderful: the dogs found stress in 675 of the 720 people. It could be 93.75% right! Australian News reported. The study's writer Clara Wilson said, "stress can change people's breath and sweat. Dogs are very good at smelling these changes." In the study, she also said, "this finding helps us learn that how dogs may know people's feelings."

④ This finding shows how special the bond is between people and dogs. The finding also tells us that dogs are very clever. And maybe dogs can help stressed people.