DDC 제23판의 본표와 보조표 일부를 발췌한 것이다. 이를 적용한 Political conditions in the 20th century의 분류기호로 옳은 것은? 320 Political Science.09 History, geographic treatment, biography Do not use for political situation and conditions; class in 320.9.9 Political situation and conditions.9001-.9008 Standard subdivisions [.9009] History, geographic treatment, biography Do not use for history; class in 320.901- 320.905. Do not use for geographic treatment and biography; class in 320.91-320.99.901-.905 History Add to base number 320.9 notation 01-05 from Table 2.91-.99 Geographic treatment and biography Add to base number 320.9 notation 1-9 from Table 2 Table 1 -0901-0905 Historical periods -0904 20th century, 1900-1999 Table 2 -01-05 Historical periods Add to base number -0 the numbers following -090 in notation 0901-0905 from Table 1