Ключевые слова: abstract, achievable, attainable, background, banner, concept, concerns, dices, dilema, doable, done, feasible, hopeless, impossible, insoluble, insolvable, insuperable, mindset, mystery, possible, problems, puzzle, realizable, resolvable, riddle, soluble, solved, unattainable, undoable, unrealizable, unsolved, word, word background, workable,