Read the passage first and then ask questions, and answer the questions after reading the passage.

the method of illustrating the column figures; Concrete, vivid, vivid.

Self-purification ability: Self-purification refers to the process of gradual and natural purification of polluted water bodies and restoration of water quality under physical, chemical and biological actions. Water self-purification in a narrow sense refers to the role of microorganisms in the water body to oxidize and decompose organic pollutants to purify the water body.

Water self-purification can occur in water, such as the dilution and diffusion of pollutants in water and biochemical decomposition in water. Can occur at the interface between water and atmosphere, such as the volatilization of phenols; It can also occur at the interface between water and water bottom, such as the precipitation of pollutants in water, sediment adsorption, and decomposition of pollutants in the substrate.

All kinds of water bodies in nature have a certain self-purification ability, which is determined by the physical and chemical characteristics of water itself, and it is also a precious wealth given to us by nature. If we can scientifically and effectively use the self-purification function of water, we can reduce the pollution degree of water bodies and maximize the benefits of limited water resources, including economic, social and environmental benefits. The self-purification capacity of a water body in a specific area and for a certain period of time is limited.

It is one of the ways to reduce or eliminate water pollution by studying and correctly applying the law of water self-purification, and taking auxiliary measures such as artificial aeration or water diversion and dilution to strengthen the self-purification ability. At the same time, the self-purification capacity of the water body is also an important decision-making factor when determining the amount of pollutants that are allowed to be discharged into the water body.

Answer: This sentence mainly uses the method of explaining the column of numbers, which can more concretely, vividly and vividly write things.

1. In the text, "treasure trove of knowledge" refers to (books), and "key" refers to (reading).

2. Briefly write the main content of the essay.

Answer: Reading is the most enjoyable thing in the world, books are a treasure house of knowledge, and reading is the key to open this treasure house, and it is the highest enjoyment of human beings. Reading is a part of life, and we can enrich our lives by reading books. Therefore, we need to be diligent in reading.

1. When describing the mountain scene, this text uses the (space) order, first write (pine), then write (grass) mountain, and finally write (sunset).

2. In this text, the author describes the mountain after the snow in Jinan in winter from the two aspects of (appearance) and (color), highlighting its (beautiful scenery) characteristics.

3. The meaning of "delicate" in the sentence "those hills are too delicate" (beautiful, very petite).

4. How do you understand "so that you want to see a little more beautiful mountain skin"? What kind of feelings does the author express?

A: My understanding is that the author compares the mountain to a beautiful little girl, using figures of speech such as metaphor and personification. It shows the author's love for the mountain.

1. When describing the mountain scene, use the (space) order, first write (pine), then (grass) mountain), and finally write (sunset).

2. From the two aspects of (appearance) and (color), the mountain after the snow in Jinan in winter is described, highlighting its (beautiful scenery) characteristics.

3. The meaning of "delicate" in the sentence "those hills are too delicate" (beautiful, very petite).

4. How do you understand "so that you want to see a little more beautiful mountain skin"? What kind of feelings does the author express?

Answer: The author compares the mountain to a beautiful little girl, using figures of speech such as metaphor and personification. It shows the author's love for the mountain.