as...as sb could 這個(gè)一般用在句尾,做動(dòng)詞的補(bǔ)語(yǔ),表示盡可能adj./adv.的去做某事例子 she is running as fast as he could.而can是情態(tài)動(dòng)詞 經(jīng)常放在謂語(yǔ)動(dòng)詞前面構(gòu)成整體的謂語(yǔ)結(jié)構(gòu)參考：can（1）“can”表達(dá)能力...對(duì)不起，我是說(shuō)as as sb. could 和 as as sb. can是否有差別as as sb. could 和 as as sb. can非要說(shuō)卻別的話前者用于過(guò)去時(shí)，后者用于現(xiàn)在時(shí)