should have done:本應(yīng)該做而沒做某事,強(qiáng)調(diào)“本來應(yīng)該”；
could have done:本可以做卻沒做某事,強(qiáng)調(diào)“本來可以”；
might have done: 可能已經(jīng)作了某事,強(qiáng)調(diào)猜測.
前兩個(gè)都是假設(shè),是與實(shí)際情況相反的假設(shè).第三個(gè)是猜測.除此之外,should have done還明顯含有懊悔或責(zé)怪之意.
舉例來講：
小明把家里的鑰匙放在教室忘記帶了.回到家打不開門一直蹲在門口等到晚上10點(diǎn)多加班的爸爸媽媽回來,很晚才進(jìn)了家門.此場景下
1. 小明到家后發(fā)現(xiàn)鑰匙忘帶很懊悔.此時(shí)他可能會(huì)抱怨自己：I should have brought the key with me.
2. 那時(shí)的小明除了在門外等待爸爸媽媽回來,還有別的解決方案卻沒做：He could have come back to school to get the key but he didn't.
又如,當(dāng)爸爸媽媽那么晚回來發(fā)現(xiàn)小明在門外,問明原因后,爸爸媽媽問他為什么當(dāng)時(shí)不返回學(xué)校拿鑰匙.爸爸媽媽認(rèn)為若小明當(dāng)時(shí)返回學(xué)校拿了鑰匙的話可能早就進(jìn)去了.爸爸媽媽可能會(huì)說：You could have come in much ealier if you came back school to get the key then.
3. 關(guān)于為什么當(dāng)時(shí)沒有返回學(xué)校拿鑰匙,小明解釋到：I thought the gate might have already been closed by that time.(學(xué)校大門那時(shí)候可能早已經(jīng)關(guān)了）
For your reference. Tks!