The Ukraine crisis is the classic case of a known unknown: We know that we don't know what Russian President Vladimir Putin intends to do as he amasses troops on the Ukrainian border.
원문출처 : https://www.cnn.com/2022/01/28/europe/ukraine-russia-explainer-war-threat-cmd-intl/index.html
원문출처 : https://www.cnn.com/2022/01/28/europe/ukraine-russia-explainer-war-threat-cmd-intl/index.html