rank nation gold silver bronze total
rank
nation
gold
silver
bronze
total
number
first second
number
number
number
number
number text(text) number number number number
1 united states (usa) 25 16 7 48
what country is the only country with at least 20 gold medals ?
WDT NN VBD-AUX DT JJ NN IN IN JJS CD NN NNS .
United States (USA)
select c2 from w where c3_number >= 20