对于规则动词的过去式,有一个小口诀“轻轻/t/,浊元/d/,t,d 之后读/id/”也就是单词以清辅音结尾变过去式就读/t/,浊辅音或元音结尾读/d/,在以辅音/t/和/d/结尾的单词中读/id/.
如
like /laik/----> liked /laikt/；change /tʃeindʒ/----> changed
/tʃeindʒd/,bore /bɔ:/----> bored /bɔ:d/；dictate /dik'teit/---->
dictated /dik'teitid/,hand /hænd/----> handed
/hændid/.而一些不规则的过去式就要特殊记忆了,如 think--->thouught.
所以啊,named /neimd/,changed /tʃeindʒd/,told /təuld/,learnt /lə:nt/.
therefore是所以的意思,没有therebefore这个单词.不过倒是有thereafter,是此后,之后的意思.