(4)circulation
n.
1.循环,环流;运行[U][S1]
We observed the circulation of blood in frogs.
我们观察了青蛙的血液循环。
2.(货币、消息等的)流通,传播[U]
Many forged notes are in circulation.
许多假钞在流通。
3.(报刊等的)发行量,销售量[S]
This paper has a circulation of more than a million.
这一报纸的发行量达一百多万份。
4.通货,货币[U]