>>269
$ ruby19 -ve 'p %q[question #{a}]'
ruby 1.9.0 (2004-12-15) [i686-linux]
"question \#{a}"
$ ruby18 -ve 'p %q[question #{a}]'
ruby 1.8.2 (2004-12-15) [i686-linux]
"question \#{a}"