James while John had had had had had had had had had had had a better effect on the teacher James while John had had had had had had had had had had had a better effect on the teacher這個英文句子是用來說明用词歧義和标点符号的重要性標點符號的作用就是代替口語中的語調重音和停頓在探討人類如何處理資訊的研究中常用這句話来說明讀者會借助標點符號來理解句子的意思尤其在掃讀多行文字時更是如此