【正文】 a liquid metal outer core. The moving electric currents inside this liquid metal create a magnetic field. The earth magnetic field is important because it protects us from the solar wind. The solar wind is a current of charge particles ing at us from the sun. when the solar wind nears the earth, the earth’s magnetic field deflects it away. This protects the earth from the radiation(輻射), which can be dangerous to life. It also protects the satellite that we use for munication. Scientists now believe that the earth’s magnetic field is about to reverse. This is called the magnetic field reversal. Every 200,000 to 300,000 years, the earth magnetic field reverses. In other words, the north and the south magnetic pole switch places. This has happened many times in earth’s history, but it has been happening more lately. Recent research provides evidence that there have been 5 magnetic reversals during the past 500,000 years. The most recent event happened approximately 41,000 years ago. Recent studies have found that the earth magnetic field has weakened about 5% per decade. As its current rate, the next reversal could happen within the next century. Some people also worry about the effects of the magnetic field reverse. They think there is a possibility that it could cause many problems. For example, without magnetic field, munications can be disrupted. Birds and other forms of lives could bee confused and get lost. Another effect will the increase in some forms of cancer especially skin cancer. This will be because of the increase in the amount of radiation absorbed by our bodies. The possibility that a field reversal will be an extinction even is very low. There is very little historic evidence to show that previous reversals have caused extinctions. Humans have been on earth for million years, during which there have many reversals. Therefore, scientists believe any changes would be temporary. Another theory is that the earth outer layer could rotate around the outer liquid mental core that make out of the earth. So in the next reversal, continent could ship positions from north to south. Imagine the effect happened, Australia would be in the northern hemisphere. With so many theories, how can we know what to believe? This is important because some of them require us to act well in advance. Otherwise, it will be too late to prevent the catastrophe. This underlines the importance of getting reliable information backed by strong evidence. L5 Unit 34 vocabularyResume, to continue or start again after a pause. After a short interruption, our work resumed and we worked for another hour. Work on the project resumed once we passed the safety inspection(檢驗(yàn)。 檢查). Interrupt, to stop something in progress. I hate to be interrupted when I’m working, but something it’s necessary. It’s difficult to have a conversation with her because she always interrupts. Reconsider, to reassert or think again about changing something. I was planning to vote against him, but after hearing him speak, I’m going to reconsider. I didn’t want to hire her at first but then I reconsidered and offered her a job. Conclude, to reach a decision, to end something or summarize the main point. To conclude my presentation, here is a summary of my remendations(建議). After hearing the arguments for and against the project, we have reached a conclusion. Anticipate, to think in advance, to predict what’s ahead. I won the game because it was easy to anticipate my opponent’s next move. He tried to anticipate what we are going to do, but he was pletely wrong, so he lost. Permanent, to be fixed or unchanging, the opposite of temporary. He plans to stay there permanently. He had decided to bee a permanent resident of China. Temporary, only lasting for a short time, the opposite of permanent. We can only offer him a temporary position in the pany. This is the kind of job he wants but it’s okay as something temporary until he can find something better. Definite, well define, precise, certain, unchanging. We can’t begin the project unless you give us a more definite schedule. We can’t give you a definite answer until we get more information. Obvious, easy to see, stand out. Of the job candidates we interviewed, he was the obvious choice. It’s obvious that he can’t afford to buy that house. Trivial, of little or no importance, insignificant. It’s a trivial detail, so there is no need to worry about it. those problems are not trivial so we need to find a solution. We don’t know their exact location, but they are definitely in this general area.After hearing arguments for and against the project, we have reached a conclusionWe have concluded that there are too many risks, so we’re going cancel the project.I’ve considered and reconsidered your request, but the answer is still no. From her facial expression, it was obvious that she really disliked him.We can’t make a reservation for your flight until you give us a definite return date. Humans lived as nomads(游牧生活) until they decided to settle down and permanent munities. We resumed watching the movie as soon as the wireless connection restored. The conclusion is often the most important part of a presentation. We don’t know the exact location but they are definitely in this general area. I’ve considered and reconsidered your request, but the answer is still no.After hearing arguments for and against the project, we have reached a conclusion. In conclusion, I think this new pesticide isn’t safe for the environment. We can’t make a reservation for your flight until you give us a definite return date. We need you to be more definite about your plans for the next 6 months. L5 Unit 34 dialogueI just heard what you did. You did it without consulting me. Yes, I talk to them I decided to invest more money. I didn’t have time to consult with you and I trust them. That’s our money, not yours. We’ve been saving it to buy a house