question: private static void expand2DigitNumber ( String numberString , WordRelation wordRelation , Item tokenItem ) { if ( numberString . charAt ( 0 ) == '0' ) { if ( numberString . charAt ( 1 ) == '0' ) { } else { String number = digit2num [ numberString . charAt ( 1 ) - '0' ] ; wordRelation . addWord ( tokenItem , number ) ; } } else if ( numberString . charAt ( 1 ) == '0' ) { String number = digit2enty [ numberString . charAt ( 0 ) - '0' ] ; wordRelation . addWord ( tokenItem , number ) ; } else if ( numberString . charAt ( 0 ) == '1' ) { String number = digit2teen [ numberString . charAt ( 1 ) - '0' ] ; wordRelation . addWord ( tokenItem , number ) ; } else { String enty = digit2enty [ numberString . charAt ( 0 ) - '0' ] ; wordRelation . addWord ( tokenItem , enty ) ; expandDigits ( numberString . substring ( 1 , numberString . length ( ) ) , wordRelation , tokenItem ) ; } }
target:  Expands a two-digit string into a list of English words.