Noise pollution is doing much harm to our health now. Noise, in fact, is unwanted sound and is a kind of invisible (无形的) killer. More and more students enjoy listening to music very much. When they listen to MP3 players, they like to turn up the volume (音量). Some people love listening to loud music. Furthermore, while watching TV, they keep the volume up. But they haven't realized that the noise is weakening their hearing. In fact, the noise not only influences each member in the family, but also makes a difference to the comfort of neighbors.

Noise pollution is a source of increasing misery (痛苦) to people in our society. If people are often disturbed by it, they may feel uncomfortable or upset. What's worse, the noise can make people mad sometimes. If a worker works in a printing factory for too long, his/her hearing loss is much faster than a common person working in a quieter environment. So everybody must pay more attention to noise pollution. Generally speaking, the following four types of noise should be watched out for:

    ◆Noise in the street

    ◆Construction site (建筑工地) noise

    ◆Noise at work

    ◆Transportation noise

    I think the local department (部门) should take measures to control the noise levels, but it's everybody's duty to keep a quiet environment.

    In recent years, there have been many breakthroughs in the AI (人工智能) field. Here, let us see four of the most interesting developments in AI in 2017.

    Different weather makes people feel different. It influences health, intelligence（智力）and feelings.

    In August, it is very hot and wet in the southern part of the United States. People there have heart trouble and other kinds of health problems during this month. In the Northeast and the Middle West, it is very hot at some times and very cold at other times. People in these states（州）have more heart trouble after the weather changes in February or March.

    The weather can also influence intelligence. For example, in a 1983 report by scientists, IQ（智商） of a group of students was very high when a very strong wind came, but after the strong wind, their IQ was 10%lower.The wind can help people have more intelligence. Very hot weather, on the other hand, can make it lower. Students in many schools of the United States often get worse on exams in the hot months of the year（July and August）.

    Weather also has a strong influence on people's feelings. Winter may be a bad time for thin people. They usually feel cold during these months. They might feel unhappy during cold weather. But fat people may have a hard time in hot summer. At about 18℃, people become stronger.

    Low air pressure（气压） may make people forgetful（健忘）. People leave more bags on buses and in shops on low-pressure days. People feel best at a temperature of about 18℃.

Are you feeling sad, tired, forgetful, or unhappy today? It may be the weather's problem.

    When you are waiting for a bus at a station, a 31-metre-long bus is coming to you. You must be surprised. In fact, the 31-metre-long bus is the longest bus in the world. And the bus comes from Germany. An ordinary bus is only about 10 metres long and it can carry only 80 people once. But the longest bus can carry 256 people. So we will need fewer buses in the future. The longest bus can save energy, too. That's to say, it will take less energy than an ordinary bus. Moreover, the driver can drive the longest bus as easily as an ordinary one.

    However, firstly, it has to spend $ 10, 000, 000 buying the longest bus. Someone jokes that we can buy a lot of ordinary buses with that money. Secondly, people think that it is hard for the longest bus to travel on the bustling streets. It may cause new traffic problems. Thirdly, it is easy for someone to get onto the bus without buying a ticket.