The bicycle is one of the simplest and most useful inventions in the world. What is most surprising is that it was not (发明) earlier, although the great inventor Leonardo da Vinci had drawn pictures of bicycles and also of flying machines and some other things. Those things were not produced until long after he (死).
A person riding a bicycle uses a little energy to make the bicycle (移动), and there is no (污染) at all when you are riding. Even so, in (发达的) countries, most people don' t travel to work by bicycle. It is not because the bicycles are expensive or people feel (疲劳的) if they ride to work. It's because the number of cars on the roads becomes (更大的). It certainly becomes more (危险的) to ride a bicycle.
As a result, more people put their bikes away and go to work in their cars, and in this way, the situation is made more serious. Perhaps the best way to make riding safer and more popular is to (创造) paths only for bicycles, and to make it so difficult and expensive for (驾驶员) to take their cars into the city that they will go back to using their bicycles.
Since computers were (invent) in the US in 1946, they have become very important in many areas(领域). There is no doubt(毋庸置疑) that computers are very (use) in technology and business. In space, computers have been used to control the speed and direction of a spaceship. the help of computers, doctors can find diseases(疾病) easily and solve other problems. For example, tiny computers which are inside patients' bodies can keep hearts beating normally. In factories, robots are controlled by computers that are human brains. They can do work that is (danger) to humans. In business, computers are used to place and cancel (取消) orders. They are also making the workplace safer and (good).
Since the Internet came into being, people'
s (life) at home have been changed, too. More and more people have (person) computers that are used to play games and watch movies. Thanks to the Internet, people can do shopping and do business at home. Instead of writing letters on paper, people communicate sending e- mails and chatting online. The whole world is connected. The Internet is making the world smaller, like a village.
Humans and animals need oxygen to exist. Without it, most living things will die. But where does oxygen come from'? Trees. Trees can take in much carbon dioxide which may be bad for our environment and produce oxygen for us to breathe.
All people know that trees are important to us. Scientists believe humans cannot live if there are no trees on the Earth.
Trees are a major source(来源) of food. Apples, oranges, lemons all come from trees. Humans and animals knew how to get food from trees many years ago.
In fact, many kinds of important medicine come from trees too. Some special things on trees can be used to produce medicine. Also, trees can make the world beautiful and relaxing. They help protect the soil.
When talking about inventors, who do you first think of? Forget Thomas Edison. Meet the teenage 1 at the 24th Jiangsu Adolescents Science &. Technology Innovation Contest(江苏青少年科技创新大赛).
Wang Xingyu, from Kunshan No. 2 Middle School, invented "a 2 line" in the zebra crossing. Wang often saw people running through
the red 3 , so he thought of an idea,
"I 4 a spray tube(喷管) in the zebra crossing. When the light is red and 5 crosses, it sprays water. If the light is 6, it will not work," said Wang.
But does it 7 water? "There's a water channel(槽) on the ground, so the water will be collected and 8 again," he said. Zong Hangchen, from Nantong Special Education Middle School, also got his invention idea from daily experience.
Zong's 9 could only feel a little light. When he walked on the sidewalk for the blind, he often came across obstacles(障碍物). Once he 10 hurt his nose.
11 help himself and the blind, Zong made something that has radar(雷达) and a loudspeaker. Users tie radar onto their knees and 12 the loudspeaker around their necks. When they meet obstacles, the radar will see them and the loudspeaker will make a 13 to tell the users.
Chen Huijuan, an official from Jiangsu Association for Science and Technology, was 14 at these inventions.
15 some ideas are simple, the creations are very good," she said. "Get inspiration( 灵感) from small things in life and you can be an, inventor, too.
