Simple console based hiragana drill tool

hiragana.rb

# -*- coding: utf-8 -*-

pairs = [["あ","a"],
["か","ka"],
["さ","sa"],
["た","ta"],
["な","na"],
["は","ha"],
["ま","ma"],
["や","ya"],
["ら","ra"],
["わ","wa"],
["が","ga"],
["ざ","za"],
["だ","da"],
["ば","ba","pa"],
["い","i"],
["き","ki"],
["し","shi"],
["ち","chi"],
["に","ni"],
["ひ","hi"],
["み","mi"],
["り","ri"],
["ぎ","gi"],
["じ","ji"],
["ぢ","ji"],
["び","bi","pi"],
["う","u"],
["く","ku"],
["す","su"],
["つ","tsu"],
["ぬ","nu"],
["ふ","fu"],
["む","mu"],
["ゆ","yu"],
["る","ru"],
["ぐ","gu"],
["ず","zu"],
["づ","zu"],
["ぶ","bu","pu"],
["え","e"],
["け","ke"],
["せ","se"],
["て","te"],
["ね","ne"],
["へ","he"],
["め","me"],
["れ","re"],
["げ","ge"],
["ぜ","ze"],
["で","de"],
["べ","be","pe"],
["お","o"],
["こ","ko"],
["そ","so","zo"],
["と","to"],
["の","no"],
["ほ","ho"],
["も","mo"],
["よ","yo"],
["ろ","ro"],
["を","o"],
["ん","n"],
["ご","go"],
["ど","do"],
["ぼ","bo","po"]]

total = 0
correct = 0

trap("INT") {  puts "Final score: #{correct} out of #{total-1} correct"; exit}
while true do
  pair = pairs[rand(pairs.size)]
  guessed = false
  while !guessed
    total += 1
    print pair[0]
    print ":"
    guess = gets.chomp
    if (pair[1..-1].include?(guess)) then
      puts "Correct!"
      correct+=1
      guessed = true
    else
      puts "Incorrect, try again"
    end
    puts "#{correct} out of #{total} correct"
  end
end