Defining the coalcity. There are 48 coal cities in our country.
对煤炭城市进行了界定，全国共有煤炭城市48座。
2
The result indicates that the technological efficiency of every coalcity of Heilongjiang Province is generally not high, but the trend of rising steadily appears.
结果表明，黑龙江省各煤炭城市的技术效率普遍不高，但都呈现稳步上升的趋势。
3
A convoy of trucks hauling coal near the Datong City number two power plant in Shanxi province.