「情態動詞+ have done」用法總結
【歸納】
★could have done可以表示「過去本來能夠做某事而實際上沒有做」。如：
I could have come here a little earlier, but I’m late because of the bad traffic.
★must have done表示對過去已經發生過的情況的肯定推測，語氣較強。如：
She must have received the book; I sent it a month ago.
★may / might have done表示對已經發生過的情況的肯定推測，語氣稍弱。might have done還可表示「本可能做某事而實際上沒有做」。如：
She didn’t come on time. She may / might have missed the bus.
He might have given you more help, but he was very busy then.
★should / ought to have done表示「本該做某事而實際上沒有做」，其否定形式表示「本不該做某事而實際上做了」，通常含有責備的意思。如：
The flowers have died. I should / ought to have watered them often.
You shouldn’t / ought not to have told them the truth.
★needn’t have done表示「本不必做某事而實際上做了」。如：
It is warm today. You needn’t have worn your coat.
注意：didn’t need to do與needn’t have done都表示「過去不必做某事」，但didn’t need to do通常表示「沒必要做，實際上也沒做某事」，而needn’t have done則表示「雖然沒必要做，但已經做了某事」。如：
He didn’t need to get up early on Sunday, so he stayed in bed until 10 am.
It’s only five minutes』 walk. We needn’t have taken a taxi.
【即學即練】用「情態動詞+ have done」結構完成下列句子。
1. You ________ (wash) the wound with cold water, but you used hot water.
2. I am not feeling well in the stomach. I ________ (eat) so much just now.
3. There was enough time. You ________ (hurry).
4. I ________ (lend) you the money. Why didn’t you ask me?
5. They ________ (go) out because the light’s out.
答案【即學即練】
1. should / ought to have washed
2. shouldn’t / ought not to have eaten
3. needn’t have hurried
4. could / might have lent
5. must have gone