Coal is most used for the electricity production in()and().

Professor Thring's mechanical coal miner ______. A: has already been seen by the Coal Board B: is his first invention C: looks like a TV camera D: is not yet in production

People are aware that coal, which has gone to mass production, is still a finite resource, though _________ than either oil or gas.

The most easily oxidized coal is (). A: lignite coal B: bituminous coal C: lean coal D: anthracite coal

1.1 tons and 8) ______ tons of steel and coal-production capacities were cut on average each second.‏‍‏

Which of the following is not a common way for coal caving? ( ) A: Top caving coal in group sequence B: Top caving coal in single cycle sequence C: Top caving coal in multiple cycles in sequence D: Top caving coal in intervals of single cycle

The coal industry is running down as coal is gradually replaced by oil.( industry )

The dry ash free volatile content of a coal is 7%, which is most likely to belong to (). A: Bituminous coal B: Anthracite C: Lignite D: Lean coal

The dry ash free volatile content of a coal is 47%, which is most likely to belong to (). A: Lignite B: Lean coal C: Anthracite D: Bituminous coal

( ) is not a real coal, but only a precursor. A: Anthracite B: Bituminous coal C: Lignite D: Peat