happy 是常用词,本义是“幸福的”,指“由于幸福、满足而感到快乐”,如: He was very happy to hear that . 听到那,他很快乐. pleasant 是常用词,指“愉快的”,强调“所形容的人或物有给予愉快的性质”,如: We spent a very pleasant evening. 我们度过了一个愉快的夜晚. glad 多用在与人见面时的客套语中,指使人感到:情绪上有短暂的喜悦,常用作表语,一般情况下不作定语.如:① I’m glad to help you with your English.我很高兴帮你学英语. merry 除“高兴”之外,还有耳目可以感到的“热闹”,一般只作定语.如: Merry Christmas!