But even this is not a sufficient explanation, because studies of how the supply of labor responds to tax changes suggest that something else must explain the enormous gap between US and Europe, especially France and Germany.
但即便如此理由也不够充分，因为对劳动力供应与税收变化关系的研究表明：美国和欧洲，特别是英法两国之间的巨大差距一定另有原因。