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.

E

Recently, China announced it had achieved success in drilling fire ice or methane hydrate (天然气水合物，即可燃冰), from the seabed in the Shenhu area of the South China Sea. It produces high amount of energy when it is burned, leaving nothing but dioxide and water.     Many countries, including the United States and Japan, have long beeaban doing research on methane hydrate, but taking it from bottom of the sea has been a common problem they are facing. According to reports, China succeeded in drilling methane hydrate for a number of days continuously and got an average of over 16,000 m3 daily. It is believed to be a big breakthrough.

Scientists say there is about 21, 000 trillion (万亿) m3 of methane hydrate in the world. If we can use it, it can meet the world's energy need for 1, 000 years. However, it is too early to say a new energy source (来源) has been found because we are still facing two main challenges—environmental risk and economic (经济的)cost. When methane hydrate is taken from the seabed, it may go into the air easily. That's very bad for the environment because methane is one of the worst greenhouse gases. Besides, drilling methane hydrate is very expensive as well.     However, China's technology breakthrough is very important because it shows the way researchers across the world should take. It also raises hopes that one day we can drill methane hydrate as a source of energy.

A

    Since the first person walked on the moon in 1969, technology has greatly helped space exploration. In recent years scientists have built a special robot to accompany astronauts on space missions (任务). Because this robot looks and moves like a person, scientists call it a humanoid robot. The latest model of the humanoid robot is known as R2, short for Robonaut 2.

    R2 was first launched into space on February 24, 2011. It was built by the National Aeronautics and Space Administration (NASA) and the car producer General Motors (GM).

    R2 weighs 330 pounds and costs $2.5 million to build. It has arms and a head- filled with vision equipment—but no legs. Its "brain", or computer, is in its stomach. R2's arms can hold 20 pounds. Each bendable finger has 5 pounds of grasping force. R2's hands are also skillful. Since its hands are shaped like human hands, R2 can use human tools to complete tasks traditionally performed by astronauts." Astronauts absolutely have their day packed from the minute they wake up until they go to bed. If Robonaut can provide just an hour's worth of relief to the astronauts doing something they don't want to do, that would make it worth it right there," says Nic Radford, the deputy project manager of R2.

    One advantage of working with R2 will be that ii can't complain about its work! Astronauts will also appreciate the fact that the robot can perform its duties without constant supervision (监管). R2 can be assigned a task and then checked on periodically. If R2 does not complete a task correctly, astronauts will be able to make minor adjustments to adapt (适应) the robot's behavior so that the task gets done right.

    R2 is still in the design stage of development, which means that scientists are frequently testing it and looking for ways to improve it. Right now, humanoid robots do not have the protective equipment needed to work outside the space station. As technology advances, humanoid robots will be able to help astronauts with dangerous tasks as well as routine ones.

    In the future, humanoid robots will be astronauts' eyes in space, going to places considered too difficult or unsafe for astronauts to explore. Some of them will be mounted on wheels to explore the surface of planets or asteroids (小行星). The robots will be able to send back videos and help astronauts gather information about the atmospheres of these places.

    One outcome of using these humanoid robots will be a greater understanding of the interaction between humans and robots. NASA engineers believe that when humans and robots combine forces and work together, the results will be better than what either could achieve alone. John Olson, a director at NASA headquarters in Washington, D.C, says that the project will allow us to go farther and achieve more than we can probably even imagine today.

    We all want to protect the environment, but we're mostly too busy or too lazy to put up big change. There is nothing new here but if you follow at least some of these tips, you can be proud of yourself in the protection of the environment.

    Use LED light bulbs: They last much longer and they can save energy.

    Donate: You have many clothes or things you want to throw. If they are still usable, give them to someone who needs them.

    Turn off your devices: When you do not use a house device, turn it off. For example, if you don't watch TV, turn it off. Turn off the light when you leave a room.

    Walk or cycle: Driving is one of the biggest causes of pollution. If you want to use your car, ask yourself the following question: do I really need my car? Walk or use your bike if the journey is a short one.

    Detergent (洗漆剂):Use less dose of detergent to wash your clothes or dishes.

    Leaky faucets(漏水龙头):Fix them, or they will waste a lot of water.

    Rainwater: Think of collecting rainwater. This water can be used for different purposes.

    All these tips will help you save money and protect the environment.

    Nowadays, computers and Internets are playing an important part in our life. Some people even say they can't live without them. We usually need to set passwords (密码) when we use computers and Internet. But not all the passwords are safe. In order to keep our accounts (账户)and personal information safe, we must learn how to make safe passwords.

    How can you make your computer and Internet passwords safe? Experts have some advice for you. You'd better remember the advice and they are useful for you. Here are the suggestions.

    Firstly, make your password out of capital(大写) letters. If your password is made of capital letters, it will be difficult for others to get into your account. It only takes a hacker(黑客) 10 minutes to work out a six- letter password made of small letters. But the same password in capital letters takes 10 hours to work out.

    Secondly, add numbers or symbols to your passwords. It may be much safer. Sometimes such password is not easy to remember, but it is really safe.

    Thirdly, never use personal information for passwords and use different passwords for different accounts. Experts say that a user should change his or her passwords every 90 days. In this way, hacker won't guess your passwords.