South Korean researchers say they have developed a skin-like material that behaves like the skin of a chameleon(变色龙). It can change colours to look like its surroundings.

The team led by Ko Seung-hwan, a mechanical engineering professor at Seoul National University created the skin with a special liquid that turns colours in different temperatures. These changes are controlled by flexible heaters made of very small wires.

If you are in a desert, and you wear forest-coloured clothing, you can easily be seen. Changing colours and forms actively with the temperature is central to the technology, Ko said. The technology uses something called thermochromic liquid crystal(水晶)and silver nanowire heaters. Thermochromic means heat causes the colours to change. Nanowires are just like normal electrical wires, but they are extremely small.

Ko and the team demonstrated this technology using a chameleon-shaped robot with colour-seeking sensors. The skin tried to copy whatever colours the sensors “saw” around it. In a video, the robot walked on red, blue and green floors. It immediately changed colour to look like its surroundings.

Ko explained when the sensors find colour information, they move that information to a very small processor. Then, the information goes to silver nanowire heaters. When the heaters reach a specified(规定的)temperature, the thermochromic liquid crystal changes its colour.

Though the skin is made of many layers, its total thickness is less than a hundred micrometers. In other words, it is thinner than a human hair. By adding more silver nanowire layers in simple shapes like lines or squares, the skin can create complex designs. “The flexible skin can be developed as a wearable device and used for fashion,” Ko said. It can also be used in military(军事的)clothing and to create designs on the outside of cars and buildings.

【小题1】In which condition does the skin-like material change its colours?

A．In the cold climate.	B．In the hot weather.
C．In different temperatures.	D．In different surroundings.

【小题2】What plays the key role in the technology?

A．A chameleon-shaped robot.

B．A sensor finding colour information.

C．Forest-coloured clothes worn in the desert.

D．Thermochromic liquid crystal with silver nanowire heaters.

【小题3】What does the fourth paragraph mainly focus on?

A．How Ko did the research.	B．How the material works.
C．How the robot changes its colour.	D．How the robot “saw” the nearby colours.

【小题4】What can we infer about the skin from the last paragraph?

A．It can be made into cars.	B．It can be applied to many fields.
C．It is a little thicker than a human hair.	D．It is popular in the fashion world.