doctor ['dɒktə] forty ['fɔːtɪ] short [ʃɔːt]所以第一个与其他不一样的是doctor
know[nəʊ] how[haʊ] now [naʊ]所以第二个是know
actress['æktrɪs] cat[kæt] father['fɑːðə]这个是father
sun [sʌn] sugar['ʃʊgə] queen[kwiːn]这三个都不一样