1,2,3,4-Tetrafluorobenzene

The four are rivers, rivers, huai, and the sea. Shang Yu Yu Yu: "Weak water, as for Heli, the waves enter the quicksand. Black water, as for the three dangers, enter the South China Sea. The river is stony, as for the river, as for the sea, as for the bottom pillar, as for Mengjin, Luorui, as for the big river, the precipitation in the north, As for the big river, it sows nine rivers in the north, and the river goes against the river, and enters the sea. In the mountains of Minshan, where the rivers flow, and where the rivers flow, and where the rivers flow, and where the rivers flow, as far as the mausoleums are concerned, the river flows north, into the sea, where the waters flow, into the rivers, and overflow, where they flow from the north of the mountains, and where they flow north, and where they flow north, and where they flow north into the sea. The river flows from Tongbai, where it flows in the mountains, and where it flows in the mountains and rivers, and where it enters the sea. The main uses are the following. First, the benefits of irrigation. The four rivers of water nourish the fertile fields, so that the fields can be irrigated, and the five mountains can be climbed. The people feed on the sky, and this water is the water, so that the people can live. Second, the convenience of the boat. Rivers and rivers can be transported by boat, promoting the transportation of goods and goods, and the exchange of commerce and goods between various places is more convenient, and it is of great benefit to the management of families and cultural exchanges. Fourth, nurture civilization. The people live together along the coast and live by the water. Exhibit the culture of the river, such as the culture of the river, the culture of Heluo, etc., which is an important source of the summer civilization. And by the water, there is such a thing as water, which enriches the lives of the people. Fifth, wait for the weather. Its waters, the shadow of the local weather, make the surrounding environment more suitable for human settlement.

The four rivers are also rivers, rivers, huai, and mountains. Their physical properties are different. Where the river is, it is not far away, the water volume is abundant, and the water flow is rapid. Its source is not yet flowing, like a giant river made in heaven, running away, it is vast and vast, and it contains majestic power. There are many terrain on the bank, or mountains stand or plains stretch, its water is due to the flow area, the upstream is clear, and the downstream is due to the accumulation of flow, and there is a little more sediment. Where the river is, the river is also, with the sediment content. The river water is rough, and the color is like soil. Its flow is on the plateau of soil, there is a lot of sediment, and the riverbed is easy to silt and divert. The water volume is not as good as the river, but its position in the summer land is not enough, and the river basin is not enough, giving birth to ancient civilizations. The river also falls, the flood season is low, and the flow rate is slightly low in the dry season. Those who live in the river and the river. The water phase is flat, and the water system is not intersected. In the Huaishui Basin, the rainfall is high, and the water source is fixed. The water is good, and the fertile fields on the bank are cultivated. However, in history, it is also affected by the shadow of the river's flooding, and the river channel may be low. The water of ancient times once flowed into the sea. The water is clear, and the flow rate is fixed. The water channel is meandering, and the land on the way is full of landforms. However, due to the diversion of the river and other reasons, its original route has been transformed, or buried or changed, but the physical characteristics of the past have been damaged by the water. These four kinds of things are rational, each has its own advantages and disadvantages, and they are all given by nature in heaven and earth. In summer, the geography, humanities, and culture of the earth all have deep implications.

The four rivers, rivers, huai river, and the river are also. Its chemical properties are different, and there is no way to study them. Where the river is, the river is also, the water volume is abundant, and there are many tributaries along the way. Its chemical composition is affected by the land area, soil, climate and the depth of human activity. Rocks and sediments dissolve in the basin, resulting in water containing many sediments, such as sediment, sediment, sulfate, etc. Moreover, due to the regional area of the river, the water in different sections is not good, and the near city is not good or affected by labor and domestic sewage. The nitrogen, phosphorus and other sediments and heavy metals may increase. Where the river is, the river is also large in sediment content. Its chemical properties are also affected by soil plateau and other factors. A large amount of sediment is composed of multiple components, which makes the degree of floating matter in the water high. In the same way, the content of sediment in the water varies with the precipitation, evaporation and landfill of the basin, and some river sections may be caused by factors such as the flow of irrigation water. The Huaihe River is also the Huaihe River. The water of the Huaihe River has its chemical properties due to the topography and climate of the basin. The distribution of precipitation in the Huaihe River Basin is uneven, which affects the water flow and chemical composition of the Huaihe River. Moreover, the surrounding industrial activities also play a role in the water, and the industrial emissions may cause the existence of heavy gold and contaminants. The pollution of the local source causes the content of nitrogen and phosphorus in the water to be reduced. The water is also the water. In ancient times, there are many kinds of water now, but its chemical properties are also special. The water from which it originated may be influenced by the earth and rock characteristics, and contains specific chemical components. In ancient times, the water was clean, or there were few phases in the water, and the water was transformed into phases. However, due to the passage of time and the transformation of the geographical environment, the water of today's water is the same, and its transformation is also different from the past.

The method of making the four-seused harp is multi-ended, and each is good at its own wonders, such as the left: One of them is made of tung material. The paulownia is made of wood, and the sound is clear, and it is natural. The way is straight, the density is appropriate, and the piano is bright and bright. The good one of the tung is to observe the wood structure, and the flaws of the grooves can only be used. Second, the method of seeking the grooves. The technique of the grooves is exquisite and subtle. From the curvature of the piano body to the depth of the groove abdomen, there is a fixed method. The initial grooves are suitable, so that the thickness of the piano body is even, and the force is balanced. The system of the groove abdomen is related to the volume and timbre. The depth of the grooves and the clarity of the grooves must be balanced. Third, the use of strings. The string player is also the mouthpiece of the piano. The string is soft, and the string is soft, and it is easy to beat; the golden string is soft, and the tone is bright, and the life is good. According to the characteristics of the piano, the people are good and still. And the coarseness of the string is also the flood of the sound, which should be considered. Fourth, the emblem of the emblem. The emblem is the place where the phonemes are. Whether its positioning is precise or not, the shadow is the rhythm of the tone. The ancient method is measured by the size, and the emblem position is not different, so that the sound is taken according to the strings, and the sound is good, so that the beauty of the composition can be formed. Fifth, the work of painting. The paint is not only beautiful, but also can be used to make the piano. The paint is good, and the paint is suitable for all. The lacquer is thick, the lacquer is thin, and the body of the piano is thin. The lacquer is mostly used on the piano, and its color is quaint and elegant, and it can enhance the quality of the piano. All this is the key to making the piano. The methods are combined, and both are indispensable, in order to make a good piano and make a wonderful sound, so that the world can enjoy it.

The four gods are in the service of the envoy, and the general things need to be paid attention to. First, the heart of reverence should not be destroyed. The four gods, the gods of rivers, rivers, huai, and huai, are in charge of the benefits of water and people's livelihood. Gu Yun: "Respect God as if God is there." In the way you act, you should be pious, and you should not be slow. Every sacrifice is made, and the people must be made. In order to show respect, you can obtain the blessing of God, so that floods will not be born, and the river will be clear and the sea will be closed. Second, follow the system. The utensils and sacrifices used in the sacrifice of the four oceans are all customized. Such as the way of sacrifice prison and the way of Gui bi, they all follow the ancient system and cannot be changed without authorization. If the system is made, it will be disrespectful, for fear of attracting God's wrath. And the sacrifices, the steps, also need to be orderly, tolerant, and not methodical. Third, the words of prayer, the prayers of the people. What the heart says, what the mouth says, comes from the heart, not from the heart. Those who ask for it, or the rain to nourish the goods, or the safety of the people, are all based on public welfare first, not their own selfishness. If it is selfish thoughts, and the heart of deception to pray, God will not do it. Fourth, it is also necessary to hold water on weekdays. Those who have water are the four of them. If the pollution is broken, the dwelling of God will not be safe. Therefore, the water is allowed to circulate, so that it is not blocked, and it is forbidden to pollute it. In this way, only then can we be able to protect God and the relationship between us, and ensure the peace of the water and the soil. In this way, in the four times, God's messengers are used in deeds, heart, defense, words, and water, and all kinds of things, and they are all cut to the heart, and the way is appropriate.