used to + 動(dòng)詞不定式描述一個(gè)過(guò)去習(xí)慣的動(dòng)作或狀態(tài),但現(xiàn)在不再繼續(xù)了.eg.I used to go to work by bus,but I go by car now.(i.e.both habits,past and present).
但used to 也可以指一個(gè)明確的過(guò)去時(shí)間(這個(gè)過(guò)去的時(shí)間狀語(yǔ)很重要),并描述一個(gè)過(guò)去的經(jīng)常發(fā)生的動(dòng)作,和目前的狀態(tài)沒(méi)有直接關(guān)系或一個(gè)暗含的對(duì)比.eg.Have you always liked walking?--Yes,I remember when I was young I often used to go for long walks on my own.這里,說(shuō)話人現(xiàn)在的習(xí)慣于此毫無(wú)關(guān)系,他現(xiàn)在也許還保持這個(gè)習(xí)慣,也許沒(méi)有,盡管這問(wèn)題暗指他現(xiàn)在還有這個(gè)習(xí)慣.此時(shí),used to 可以用would 替換.i.e.When I was young,I would often go for long walks on my own.
would 的這種用法只見(jiàn)于敘事文章中,而不用于日常對(duì)話中.
當(dāng)used to 用來(lái)指一個(gè)過(guò)去的習(xí)慣且現(xiàn)在已經(jīng)停止,則不能用would 替換.eg.This sort of novel used to be very popular(but it isn't now).
總而言之,如果句子中有一個(gè)特定的過(guò)去時(shí)間狀語(yǔ),則既可以用used to也可以用would,反之,如果沒(méi)有這個(gè)特定的過(guò)去時(shí)間狀語(yǔ),則只能用used to 因?yàn)樗硎镜倪@個(gè)過(guò)去習(xí)慣動(dòng)作現(xiàn)在已經(jīng)停止