direct current compare alternating currentTopics Engineeringc2直流;直流电流 - District of Columbiain the US
美国哥伦比亚特区 Washington, DC 华盛顿(哥伦比亚特区)
CultureThe city of Washington, DC covers all of the land of the District of Columbia, which is on the east side of the Potomac River and belongs to the US government. The District of Columbia was established by Congress in 1790 and contains many government buildings. The land was originally given by the states of Virginia and Maryland, though Virginia later took back its gift. People who live in the district were not allowed to vote for the US President until 1961.