String (String verb) { String pastParticiple = generateHeuristicDoubledFinalConsonantPastParticiple(verb); if (pastParticiple != null) return pastParticiple; if (DOUBLED_FINAL_CONSONANTS.contains(verb)) return verb + verb.charAt(verb.length() - 1) + "ed"; for (String prefix : PREFIXES) { if (verb.startsWith(prefix) && DOUBLED_FINAL_CONSONANTS.contains(verb.substring(prefix.length()))) { return verb + verb.charAt(verb.length() - 1) + "ed"; } } return null; }