The world will face a serious energy crisis due to the gradual reduction or even final exhaustion of oil resources. Therefore, all countries in the world are actively looking for renewable energy that can replace petroleum products, among which biodiesel is an important bioenergy. When it comes to the raw materials of biodiesel, we may think of rapeseed and soybean. Biodiesel processed with their "in vivo" oil can effectively reduce carbon emissions. However, these two crops have a long planting period and occupy a lot of cultivated land, which will lead to the problem of "competing for food with people and land with food", thus leading to the embarrassing result of "solving the energy crisis, but there is a food crisis". At this time, microalgae entered the sight of scientists.

② Microalgae is an ancient lower plant, which is widely distributed in ocean, freshwater lake and other waters. Microalgae can directly use sunlight, carbon dioxide and simple nutrients containing nitrogen, phosphorus and other elements to grow rapidly, and synthesize a large amount of oil in cells. Therefore, microalgae provide a new oil resource for biodiesel production.

③ Compared with oil plants such as soybean, rape and jatropha curcas, the growth cycle of microalgae is short, from birth to oil production only takes about one week, while oil plants such as soybean generally take several months. In addition, microalgae have high oil content and high oil yield. The oil yield per unit area is several hundred times that of soybean, and tens of thousands of liters of biodiesel can be produced per hectare. Microalgae will not occupy cultivated land, and "microalgae oil field" can be developed on a large scale by using seawater and groundwater in beaches, saline-alkali land, deserts and desert areas, without competing with crops for land and water.

④ Microalgae can also fix a lot of carbon dioxide in the process of culture, so the production of biodiesel by microalgae can greatly reduce the emission of carbon dioxide. According to the calculation, every 1 ton microalgae needs to consume about 2 tons of carbon dioxide. In addition, microalgae can make use of nitrogen, phosphorus and other nutrients in wastewater in the process of photoautotrophic culture, thus reducing eutrophication of water. Therefore, microalgae can also be used to purify wastewater discharged from factories and municipal domestic sewage.

⑤ At present, China has started the first microalgae energy 973 project "Scientific basis for large-scale preparation of microalgae energy". The project is expected to develop a "microalgae resource bank" within five years to provide algae species suitable for growing in different places and different climatic conditions in China. In the future, when building "algae-mining oil fields", all localities can choose suitable microalgae varieties from the resource pool. The project will also deeply study the mechanism of microalgae products, and strive to improve the production efficiency of microalgae oil and reduce its cost. In addition, the project will also establish a pilot system by studying photobioreactor, culture technology, harvesting, oil processing and comprehensive utilization of algae cells, comprehensively evaluate the technical, economic and environmental indicators of microalgae oil production, and vigorously promote the industrialization process of microalgae energy in China.

1. Besides pointing out that microalgae are ancient lower plants, what are the four characteristics of microalgae? (4 points)

2. What are the two main methods of interpretation used in paragraph (3)? What are the benefits? (4 points)

3. What problems need to be solved in the research project of "Scientific basis for large-scale preparation of microalgae energy" in China 7 (3 points)

4. From the full text, why is microalgae energy "recyclable" and "green"? (4 points)

Answer:

1. is widely distributed, diverse, fast growing and rich in oil. (4 points)

2. Compare and list the figures. Contrast makes the advantages of microalgae more prominent, and charts make the explanation more accurate and enhance the scientific nature of the article. (4 points)

3.① Provide algae species suitable for growing in different places and different climatic conditions in China;

(2) Deeply study the mechanism of microalgae products to improve oil recovery efficiency and reduce cost;

③ Comprehensive utilization research and establishment of pilot system. (3 points)

4.① Microalgae have short growth cycle and high oil yield, and will not compete with crops for land and water.

② Cultivating microalgae can fix a lot of carbon dioxide and reduce carbon dioxide emission. Lowering water body

Eutrophication can also purify wastewater and sewage. (4 points)