pfd 英 [ˌpiː diː ˈef] 美 [ˌpiː diː ˈef] 基本解释 personal flotation device 同首字母单词 p [pi:] pa [pɑː] paal [pɑːl] paba pablum ['pæbləm] pabouche [pɑː'buːʃ] pabulum ['pæbjʊləm] pabx pac [pæk] paca ['pækə] pacchionian pace [peɪs]