According to a new survey, students' safety has become a big problem. Nearly 50% of students say they are worried about robbery on the way to and from school. Now in main big cities in China, some schools have taught an unusual lesson: self-protection. Students like this lesson because there are no exams or boring classes. And they can learn how to save lives and know how to stop danger before it really happens.

      Chen Haoyu, a teacher at Beijing No. 25 Middle School, gives young students advice on how to deal with danger.

★If you are robbed

     Keep calm. lf you can not cry for help or run away. Give the robber your money. Try to remember what the robber looks like and tell the police later.

★If you are in a traffic accident

     If a car hits you. You should remember the car number. If it is a bicycle, try to call your parents before you let the rider go. This is because you don't know how seriously you are hurt

★If it is raining hard and there is lighting

    Don't stay in high places and stay away from trees.

★When there is a fire

    Get away as fast as yon can. Put wet things on your body and try to find an exit. Do not take the lift.

★If someone is drowning

     If you can't swim, don't get into the water. Cry out for help.

      Remember that danger is never as far away as you think. Take care of yourself at all time!

    Butterflies are common all over the world，but butterflies in hotter countries are usually bigger and more brightly colored than those in cooler countries，and there are more different kinds．

   Usually the male butterflies are more brightly colored than the females．The females have bigger and heavier bodies since they carry the eggs．The bright colors of the males help to attract the females，and the duller colors of the females make them less likely to be caught by enemies before they have laid their eggs．

   Some butterflies have bright pattern colors on the upper surface of their wings that show when flying ,but when they rest on a tree or leaves , they close their wings．On the undersides of their wings there are green and brown marks which look like the tree or leaves．They are then difficult to be seen．The best example of this is the Dead Leaf Butterfly．When its wings are c1osed，it looks exactly like a dead leaf．There are even marks that look like the holes in a dead leaf．When the butterfly is run after by a bird，it closes its wings and seems to have disappeared completely．

Under the beauty of their colorful covers, the butterflies have their own way to avoid being killed by their enemies. So do the other animals. That's the rules of the nature and also the gifts that were born with.Many butterflies have round marks on their wings that look like eyes.The round marks have a useful function(功能)．When the butterflies are resting，their wings are closed，and these marks can't be seen. When a bird sees one，and begins to attack it，the butterfly will open its Wings. The bird thinks that it sees two eyes staring at it，frightened，and flies away.

    One of the hottest places on Earth is Death Valley. It's a desert valley in North America. The animals in Death Valley don't use technology to keep cool. They have special abilities that help them live there.

    During the day in Death Valley, it gets hotter than 100°F. The kangaroo rat rests all day in a hole in the ground. It covers the hole with grass to keep out the heat. The kangaroo rat comes out at night when it is cooler. This little rat is also very good at saving water. It gets all the water it needs from the food it eats. The Sun makes the desert sand very hot. One snake, called the sidewinder, can solve this problem. When it travels, the sidewinder bends (弯曲) its body into a "W" shape. Then it uses the bottom parts of the "W" like legs and walks sideways (向一侧). That way it touches only a little of the sand at a time, so the hot sand doesn't bum the snake. This strange way of moving is how the sidewinder got its name.

    A lot of water in the desert is too salty for most animals to drink. One kind of fish, the desert pupfish, can live in these salty water because it can drink the salt water.

    In most parts of the world, many students help their schools make less pollution. They join environment clubs. In an environment club, people work together to make our environment clean.

    Here are some things students often do.

    No-rubbish lunches. How many lunch bags do you throw away after lunch? Environment clubs ask students to bring their lunches in bags that can be used again. Every week they will choose which classes make the least rubbish and report them to the whole school.

    No-car day. On a no-car day, nobody comes to school in a car including the students and the teachers. Cars give pollution to us, so remember:

    Walk, jump, bike, or run!

    Use your legs! It's lots of fun!

    Turn off the water! Do you know that some toilets can waste twenty to forty cubic (立方) meters of water an hour? In a year, that would fill in a small river. In the environment clubs, students repair those broken toilets.

    We love our environment. Let's work together to make it better.