英语专业四级是什么证书？好考吗？

正确答案：Computer The twentieth century witnessed great changes in the whole world: economic boom industrial development and raise in people's living standards to which technological evolution contributed a lot. Among all those inventions which was the greatest one? Different people have different views. Some think the greatest invention was television while others believe it should be atom energy. But as far as I am concerned in terms of the depth of influence no other inventions can be compared with computers which would remain unrivalled even for another one hundred years. First of all computers save a great deal of effort people spend on calculating. Before computers were invented people had to calculate manually. Sometimes it took scientists weeks even months to work out a result daring the course of which they might make mistakes and the accuracy of data was in turn affected. But with the help of computers people are freed from heavy calculation. It only takes seconds to have a result which used to take weeks in the past. Moreover not only the speed but also the accuracy is improved to a large extent. Computers can also simulate different environments that can't be created in real life. In the science research sometimes scientists need to have a simulation environment to improve their theories or as a basis of further research. Without computers it would be difficult to have accurate and reliable results. But computers can make everything easy. Just input programs and data everything will be done. With computers the storage of information has become easier which in turn has increased the whole world's efficiency. At banks post offices and supermarkets people no longer need to queue for a long time because computers help the working staff increase their work efficiency — files and data stored in computers can be located in a very short time and their chances of getting lost are lowered to a large extent. Computers' influence has been further reinforced with the appearance of Internet which was developed based on the local area network (LAN) of computers. Today Internet has become the fastest developing medium in the world and you can do almost everything you need on it: communicating with friends reading news watching movies listening to music etc. But you must do all the above things on a computer. Although many other inventions of the 20th century brought great convenience to human or changed people's lives computers have the most valuable contribution to human and it will have much more contribution in the future.
Computer The twentieth century witnessed great changes in the whole world: economic boom, industrial development and raise in people's living standards, to which technological evolution contributed a lot. Among all those inventions, which was the greatest one? Different people have different views. Some think the greatest invention was television, while others believe it should be atom energy. But as far as I am concerned, in terms of the depth of influence, no other inventions can be compared with computers, which would remain unrivalled even for another one hundred years. First of all, computers save a great deal of effort people spend on calculating. Before computers were invented, people had to calculate manually. Sometimes it took scientists weeks, even months to work out a result, daring the course of which they might make mistakes and the accuracy of data was in turn affected. But with the help of computers, people are freed from heavy calculation. It only takes seconds to have a result which used to take weeks in the past. Moreover, not only the speed but also the accuracy is improved to a large extent. Computers can also simulate different environments that can't be created in real life. In the science research, sometimes scientists need to have a simulation environment to improve their theories or as a basis of further research. Without computers it would be difficult to have accurate and reliable results. But computers can make everything easy. Just input programs and data, everything will be done. With computers, the storage of information has become easier, which in turn has increased the whole world's efficiency. At banks, post offices, and supermarkets, people no longer need to queue for a long time, because computers help the working staff increase their work efficiency — files and data stored in computers can be located in a very short time and their chances of getting lost are lowered to a large extent. Computers' influence has been further reinforced with the appearance of Internet, which was developed based on the local area network (LAN) of computers. Today, Internet has become the fastest developing medium in the world and you can do almost everything you need on it: communicating with friends, reading news, watching movies, listening to music etc. But you must do all the above things on a computer. Although many other inventions of the 20th century brought great convenience to human or changed people's lives, computers have the most valuable contribution to human, and it will have much more contribution in the future. 解析：  在上个世纪，世界发生了巨大的变化。题目要求考生自己命题，淡谈自己认为20世纪最应该记住的发明是什么。
  文章本身并不难写，首先要确定自己的观点，就是20世纪最重要的发明是什么。所谓“最应该记住”，就是说它对整个世界的变化影响最大。写作时，可以有两种方法：一种是一一列举该发明的重要性，对社会的发展、人们的生活有什么重大的影响，论证时还可以用反证法说如果没有这种发明世界会怎么样；另外一种就是在列举该发明重要性的同时，将它和其他较为重要的发明进行对比，从而更加凸显其重要性。

正确答案：B

正确答案：A

正确答案：A