The hard work of building facilities for enriching uranium is precisely what the Iranians are now already doing, if not yet in sufficient quantity to make a bomb, which might take them five or ten more years to acquire. But, once they acquire sufficient capacity, only the easy steps will remain.
建设铀浓缩设施这个难点正好是伊朗人已经在做的事情，或许数量还没有达到足够制造原子弹的程度（可能需要五年或十年的时间），不过，一旦他们掌握了足够的生产能力，剩下的就只是那些简单的步骤了。