New York's iconic, blue-green statue of liberty wasn't always green. When the statue was gifted to the US from France in 1885, she was actually a shiny copper color. A new video reveals the chemical reactions involving oxygen and even air pollution that led to her color change from copper to liberty green. The statue of liberty was a gift from France to the US as a way of commemorating the US's fight for independence, as well as their own aspiration for democracy.

    A video, published by the American Chemical Society, explains that the 305-foot (93 meter) statue was built over nine years in sections of copper skin on top of an iron skeleton.

    In her first few decades in the Big Apple, the statue slowly turned from that shiny copper color to a dull brown and the, finally, to the blue-green, or as they'd say back in France, 'verdigris' we see today,' said the video's narrator.

When it changed color, some officials suggested restoring her back to her original color, but after the public protested against this decision, she was left the way she is. The statue's color change was as a result of oxidation reactions between copper and the air. But it was more than one reaction - the color change is due to about 30 years worth of different reactions leading to a mixture of greenish minerals.

    Oxidation reactions happen when an atom loses an electron to another atom.

    In the case of the statue of liberty, her color change was bound to happen due to oxygen in the atmosphere that is 'hungry' for electrons. On top of this, elements of New York City's polluted air added to the color change too.

The first chemical reaction of the color change involved copper giving up electrons to electron-hungry oxygen in the atmosphere. This led to a mineral called cuprite - which is pinkish red.

    Then, cuprite loses even more electrons to oxygen, forming a new mineral（矿物质） called tenorite, which is blackish in color. The black color of tenorite explains why the statue got darker over time, forming a dark brown color.

    Then, further chemical reactions occurred when sulfur（硫） in the atmosphere reacts with oxygen to form sulfur dioxide. Sulfur comes from natural processes such as volcanic eruptions, but also from man-made emissions from boats, cars, airplanes and factories. When sulfur dioxide in the atmosphere reacts with water, it produces sulfuric acid. Sulfuric acid forms green minerals with copper oxides, so the sulfuric acid in the atmosphere made the state green over time.

    Added to that, chloride from the sea spray surrounding Ellis Island where the statue is located made the statue even greener.

    The statue stayed this way for over 100 years because the exposed copper is now oxidized and stable, but the statue wouldn't be the same anywhere else.

    Recently, people in US education have gotten extremely worried because a new report has shown that American students have a math problem.

    The 2015 Program for International Student Assessment(评估)(PISA) shows math scores in the US getting lower and no improvement in science or reading. PISA tests 15-year-olds from different countries and regions in their math, science and reading skills. About 540, 000 students from 72 countries and regions took part in the assessment in 2015.

    US scores in reading and science were about the same as three years ago, leaving Americans near the middle of the bigger group. But the situation in math is much more worrying. The US average score was 470, below the OECD(经合组织)test average of 490, meaning the US was No. 40 among the 72 countries and areas. It was 12 points lower than in 2012 and 18 points lower than in 2009. So, what is going on with American students' math skills?

    One reason may be that the US does not teach math in enough depth. "Students are often good at answering the first part of a problem in the United States, "said Andreas Schleicher, director of education and skills at OECD. "But as soon as students have to go deeper and answer the more complicated part of a problem, they have difficulties. "In comparison, many high-performing countries and regions in math teach a lot less but focus in much greater depth,  especially when you look at East Asia, Japan and Singapore, according to Schleicher.

    Another reason may be the fact that many people in the US are unwilling to travel to foreign countries to learn better teaching practices. "One of our biggest challenges in the US is that the teachers are not going out and seeing what high-performing countries do differently, "said Wendy Kopp, who started Teach for America, in a news program.

    We offer some kinds of courses. Each course has been designed to help students according to their needs.

    Course 1: High School ESL

    Why not make the most of your time studying in Australia with the help from TIES? We have High School ESL classes each week specifically designed for international students. Tuesday to Friday: 10:00 am to 12:00 am, $25 per hour.

    Course 2: One on One

    If you are interested in some One on One lessons with TIES teachers, we can design a course to meet your needs. One on One lessons can improve your English language skills more quickly and help students who want to take TOEFL. Tuesday to Friday: 2:00 pm to 5:00 pm, $ 80 per hour.

    Course 3: General English

    General English is designed to develop students' basic communication skills in speaking and pronunciation, reading, listening, writing, grammar and vocabulary. Tuesday to Friday: 9:00 am to 11:00 am, $ 288 per week.

    Course 4: Night Classes

    Do you want to improve your English and get the best possible results in your GRE test? We have two night classes each week designed to meet your needs. Tuesday and Thursday evenings: 8:30 pm to 10:30 pm, $60 per day.

    UK is becoming a popular destination for people who wish to study abroad. However, Britain is quite an expensive place to study and live in. Tuition fees have now reached £ 9,250 a year and students also face some of the highest living costs in the world.

    Fortunately, there are a number of countries where universities offer degree programs entirely in English, along with the chance to learn the local language while you live there. Here are three of the options.

    Tianjin University

    Moving to China is not for the faint hearted. Undergraduate degree courses at Tianjin last four years. Living costs are only around £ 400 a month and tuition fees are £ 2,300 a year. Flights will cost £ 3,600 over the four years. The total cost, at £ 28,800, is still around half that of a three-year degree in Britain. Tianjin is one of the world's latest cities and is only a half-hour train ride from Beijing. Three undergraduate programs are offered in English: Chemical Engineering, Environment & Energy and Pharmaceutical Science.

    University of Amsterdam

    The Dutch capital is not a cheap city to live in, but standard tuition fees of £ 1,800 a year make it significantly cheaper than a British degree. There are 14 bachelor's degrees on offer that are taught in English, including Political Science, Economics & Business Economics and Actuarial Science. Nearly all Dutch people speak English, making it an easy country to get by in.

    University of Milan

The University of Milan's fees range from £ 140 to £3,650 a year. The one bachelor's degree offered entirely in English—Political Science is a three-year course. While living costs in Milan are high, the significantly lower fees make it a cheaper option than a British university.

    Back in 2009, China was wrongly accused by the West of "controlling" the Copenhagen talks on climate change. By then China had truly carried out strict policies to reduce the energy consumption of economic activities and at the international level, the top Chinese leaders participated in round-clock efforts to cooperate with the major players to build a united front for efforts to solve global warming. But China was finally misjudged.

    This misjudgment caused China's scholars to rethink China's climate change communicative ways. Among them was Zheng Baowei, journalism professor of Renmin University of China, who realized China had to better shape its communication on its environmental protection.

    Delightfully, the efforts have paid off. Zheng set up a top-level international group advising his research team. He is in charge of doctoral candidates on climate change communication. Climate awareness surveys have been conducted, and a package of communication tools has been designed. Many seminars have been arranged.

    Recently, he arranged a seminar on climate change and health communication on the changing situation both in China and the world. First of all, this stressed that China's policy has developed from reducing its energy consumption and pollution prevention to the important goals of achieving a "Beautiful China" and "'Healthy China, "while coming up with plans to realize an ecological civilization since late 2012. With such goals, China played a leading role in securing the Paris climate change deal in 2015 together with the United States and European Union. In Paris, China promised to let out its carbon to the maximum in 2030.

    It is a demanding job communicating climate change and other topics of lasting development well. Despite that, some foreign scholars have realized China's smart ways in presenting the green concepts. They appreciated China's idea of building a "Beautiful China" and "Healthy China" and said it can he expanded into an idea of a "Beautiful World" and "Healthy World".

    Looking back from how China had followed the steps of the industrialized countries in advocating climate fight, people find now its own green ideas are being recognized.

You are what you wear. Clothes are important and necessary to us, but do you know how to choose suitable clothes in a correct way?{#blank#}1{#/blank#}. 

 When you go shopping and want to buy some clothes, you should think about which kind of clothes you really need and decide how much money you can spend on them.{#blank#}2{#/blank#}They tell you how to take care of the clothes. The label(标签) for a shirt may tell you to wash it in warm water. A sweater label may tell you to wash it in cold water. The label on a coat may say"dry cleaning only"and cleaning in water may destroy this coat.{#blank#}3{#/blank#}. 

 Many clothes today must be dry-cleaned.{#blank#}4{#/blank#}When buying new clothes, you had better check if they need to be dry-cleaned. You can save money if you buy clothes that can be washed or that are well made. Well-made clothes last longer. They still look good after they have been washed many times. 

Clothes that cost more money don't always mean they are better made.{#blank#}5{#/blank#}On the other hand, less expensive clothes may sometimes look better and fit you well.

A. Dry cleaning is expensive.

B. Here are some suggestions for you.

C. They may not fit you, either.

D. We need to know how to look after the new clothes.

E. If you do as the directions say on the label, you can keep your clothes looking their best.

F. Then look at the labels that are inside the new clothes.

G. The quality of clothes should be considered.