Rivers were used for trade with other cities and countries, for transportation, and for food and sustenance, among other things.
The sentence "others refer to them as giant rivers of ice" is in the present tense. The past tense would have used referred, the future tense would have used, will refer.
they can be but some are not. Rivers are not usually used unless they are spring rivers.
Lakes and rivers are used for drinking water.
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The rivers were used for fishing, transportation, baths, and drinking water. Also for trading.
The rivers have bean used fur a long time!
Tributaries
Nate rivers
Canals and navigable rivers are used extensively in Germany for transporting goods.
Illinois rivers are used for sports fishing. Some are used for barge traffic.http://www.mvr.usace.army.mil/Missions/Navigation.aspx
Lakes and rivers were used for transportation,drinking,and bathing in pioneer times.
what has sulfur been used in the past?what has sulfur been used in the past?