| Select | | View | Download | | 20.1 Fossil fuels as a major energy source | | |
| 20.2 Refining of petroleum | | |
| 20.3 Gradation in properties of petroleum fractions | | |
| 20.4 Demand and uses of petroleum fractions | | |
| 20.5 Combustion of hydrocarbons | | |
| 20.6 Burning of fossil fuels and global warming | | |
| 20.7 Air pollution arising from burning of fossil fuels | | |
| 20.8 Measures for reducing the emission of air pollutants from burning of fossil fuels | | |
| 20.9 Pros and cons of using alternative energy sources | | |
| 20.1 Fossil fuels as a major energy source (bilingual version) | | |
| 20.2 Refining of petroleum (bilingual version) | | |
| 20.3 Gradation in properties of petroleum fractions (bilingual version) | | |
| 20.4 Demand and uses of petroleum fractions (bilingual version) | | |
| 20.5 Combustion of hydrocarbons (bilingual version) | | |
| 20.6 Burning of fossil fuels and global warming (bilingual version) | | |
| 20.7 Air pollution arising from burning of fossil fuels (bilingual version) | | |
| 20.8 Measures for reducing the emission of air pollutants from burning of fossil fuels (bilingual version) | | |
| 20.9 Pros and cons of using alternative energy sources (bilingual version) | | |
| Hydrocarbons from fossil fuels (combined version) | | |
| Hydrocarbons from fossil fuels (bilingual, combined version) | | |