分享给好友:
Coal Ruth Daly
Coal
Ruth Daly
The United States has approximately 272 million tons (247 million tonnes) of coal in its reserves. About 93 percent of the coal mined in the United States each year is used to make electricity. Learn more about this natural resource in Coal, one of the titles in the Natural Resources series.
查看Ruth Daly的全部作品 ( 例如 Hardcover Book , Paperback Book 及 Book )