| 1 | Coal, granite, lapis lazuli and other. | |
| 2 | The miners excavated the coal using traditional manual methods. | |
| 3 | Our company uses natural gas instead of coal to protect the environment. | |
| 4 | Recently, the country announced that it will gradually reduce its dependence on coal. | |
| 5 | In order to generate enough electricity, the power plant requires a large amount of coal each year. |