In our daily life, robots are often found to do work that is too dangerous, boring, difficult, or dirty. And we often see kids play with toy robots.
But what exactly is a robot? There are some important characteristics (特征) that a robot must have. These characteristics might help you to decide what is and what is not a robot. It will also help you to decide what you will need to build into a machine before it can be considered a robot. A robot has these important characteristics.
Sensing First of all, your robot would have to be able to sense the environment around it. Give your robot sensors (传感器): light sensors (eyes), touch sensors (hands), chemical sensors (nose), hearing sensors (ears) and taste sensors (tongue).
Movement A robot needs to be able to move around its environment. It can move on wheels, walk on legs or be driven by small engines (发动机). A robot can move either the whole body or just parts of it.
Energy A robot needs to be able to power itself. Some robots might power itself with sunlight, some might with electricity, while others with the battery (电池). The way your robot gets its energy will depend on what your robot needs to do.
Intelligence A robot needs some kind of "smarts". A programmer is the person who gives the robot its "smarts". The robot will have to have a certain way to receive the programme so that it knows what it is to do.
Most cars get their energy from。petrol (汽油). But some cars use electricity. They get their power from large batteries (电池). There are also some cars that have both an electric motor and a petrol motor. They are called hybrid cars.
Most people think of electric cars as a new invention, but they have been around for a long time. In the late 19th and early 20th centuries electric cars were popular because the technology for petrol engines was not highly developed. But when the petrol engines became easier to make and more powerful, they became more popular. Interest in electric cars was high in the 1970s and 1980s because oil became very expensive. Recently, electric cars have again become popular because people want cars that pollute less.
Electric cars are better than petrol cars in several ways. The biggest benefit is that they can reduce pollution. In areas with a high percentage of electric cars, there is less pollution. But it is important to understand that electric cars still cause pollution. The electricity to power electric cars has to come from a power station. Unless these power stations run on solar or wind energy, they are most likely burning fossil fuels (化石燃料). The second benefit of electric cars is a reduction in the dependence on foreign oil. Since electric cars can run on electricity from coal or nuclear power (核能) stations, there is less of a need to import oil.
There are some problems with electric cars as well. One disadvantage is that electric cars are more expensive than petrol cars. This is mostly because of the high cost of the batteries. They need to be charged in special places. Right now, there aren't enough places where people can charge the batteries. Another problem is that electric cars cannot travel as far as petrol cars. Some people are afraid that the battery will run out of electricity before they reach their destination.
Despite these problems, many people, including car industry experts, believe that the percentage of electric cars will increase in the future.
① throw away a pencil without completely using it
② collect waste things for recycling
③ go to school by bike instead of by car
④ turn off the tap while brushing our teeth
⑤ keep the lights on day and night
Life in 20 Years
Life will be much better in 20 years. Now let me imagine something about it.
In 20 years, life will be different. (我们每天穿的衣服将会更多彩、更漂亮。) They will be lighter, warmer, and they don't need washing. (我们不需 要在家做饭。)We just need to make an order on the Internet and delicious food and drinks will be sent to us before dinner. (在......的帮助下)robots, we will be able to travel under the sea. There will be more funny places for people to relax. (学生们将不必在学校里学习) because they will study on computers at home. (对20年后的生活进行感叹) Don't you think so?
