人进行呼吸时，呼出的气体和呼入的气体相比，其变化时（　　）

①温度升高  ②水分增加  ③氧含量略增加  ④氧含量大增  ⑤二氧化碳含量增加．

    China has more than 30 intangible cultural heritage recognized by the UNESCO, including paper-cutting, the Dragon Boat Festival, Peking Opera, acupuncture(针灸)and so on. The organization adopted a decision that China's “The Twenty-Four Solar Terms” (二十四节气)should be put on the Representative List of the Intangible Cultural Heritage of Humanity in 2016 in Ethiopia.

    The Twenty-Four Solar Terms, knowledge of time and practices in agriculture, starts from the Beginning of Spring and ends with the Greater Cold, moving in cycles. It developed through the observation of the sun's annual movement in China. In ancient time, the method of tugui, earth sundial(日暑), was used to measure the shadow of the sun for determining the solar terms.

    The Twenty-Four Solar Terms came into being and developed in close relationship with Chinese agricultural production. At the initial stage of agricultural development, people began to explore the seasonal rules in the agricultural production to meet the needs in seeding, harvesting and other activities. Gradually, they formed the concept of “seed in spring, grow in summer, harvest in autumn and store in winter”. During the spring and autumn periods, the agricultural production was highly influenced by the seasonal changes, thus forming the concept of Solar Terms.

    As a traditional Chinese knowledge system of time with a history of thousands of years, the Twenty-Four Solar Terms clearly expresses the concepts of respect for nature, and harmony between man and nature. Created by Chinese ancestors, it have functioned as a complete set of weather calendar(日历)to guide the agricultural production in China. It has also been introduced into North Korea, Japan and other neighboring countries and still used in Japan. The Chinese heritage has provably influenced the people's way of thinking and behaving and will continue to be an important carrier of Chinese cultural identity.

一个正方体的水晶硅，体积为100cm³,它的棱长大约在      （    ）

    People have used pigeons to carry messages to one another for hundreds of years. In fact, pigeons were a common way to send messages right up through Would War II.

    In 1815, English troops were fighting Napoleon's forces in France, and the English were believed to be losing. A financial panic swept over London. Government bonds（债券）were offered at low prices. Few people noticed that Nathan Rothschild, an English banker, was snapping up these bonds when everyone else was trying to sell them. A few days later, London learned the truth: the Duke of Wellington had defeated Napoleon at the battle of Waterloo. The value of the bonds soared（暴涨）, and Rothschild became wealthy…all because his pigeons had brought him news of the victory before anyone else knew of it.

    Carrier pigeons were used by countries in both World War I and World War II. Not only were the birds often the fastest, most reliable way to send messages, they could also be used to reach soldiers far behind enemy lines, where radios and field telephone lines were useless. Since they could easily be released from airplanes or ships, every branch of the armed services used the birds.

    Carrying messages could be a dangerous job. Some pigeons performed with such bravery that they became famous and were even awarded medals. The most famous pigeon of all may have been Cher Ami. Stationed in France during World War I, he carried twelve important messages for American forces. On his last mission, though wounded, he carried a message that saved the lives of 194 American soldiers. For his amazing service, he was awarded the French “Croix de Guerre.”

    Today, modern communication methods can carry information from one place to another hundreds of times faster than a pigeon could do it. However, few people would argue with the fact that carrier pigeons — especially those that served in the military — have earned their place in history.