1
could + 动词原形 (过去能力)
He could run fast when he was young.
他年轻时能跑得很快。
can的条件式
先理解核心含义，再看它在真实句子里的用法。
can的条件式
conditional of can
He could run fast when he was young.
他年轻时能跑得很快。
Prepare the learner guide for this word
可生成：学习解释 Learner guide。只有点击后才会开始生成。
can的条件式
conditional of can
could
Base
原形
could
3rd person
第三人称单数
could
Past
过去式
情态动词 could 没有 -ing 形式或过去分词，也不使用普通的第三人称单数 -s 变化。
I could read before I started school.
我上学前就会阅读了。
Could you speak a little more slowly?
你可以说得稍微慢一点吗？
The delay could cause more problems.
这次延误可能会引发更多问题。
He could run fast when he was young.
他年轻时能跑得很快。
用 could 比 can 更委婉礼貌。
Could you help me with this box?
你能帮我搬这个箱子吗？
It could rain later.
待会可能下雨。
Not this
I could swim very fast now.
Use this
I can swim very fast now.
could 表示过去的能力或委婉语气，不能用于陈述现在的能力，现在能力应用 can。
Not this
If I had more time, I would go to the party.
Use this
If I had more time, I could go to the party.
在虚拟条件句中，would 表示意愿，could 表示可能性或能力；这里表示‘可能去’，应使用 could。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
可能是
It could be a mistake.
这可能是个错误。
本来可以
I could have helped you.
我本来可以帮你的。
不能；无法
I could not believe my eyes.
我无法相信自己的眼睛。
你能……吗
Could you open the window?
你能打开窗户吗？
我可以……吗
Could I have your name?
我可以知道你的名字吗？
它可能
Could it be true?
这可能是真的吗？
毫不在乎
He couldn't care less about the rules.
他对规则毫不在乎。
需要；想要
I could do with a cup of coffee.
我需要一杯咖啡。
我敢发誓
I could have sworn I locked the door.
我敢发誓我锁了门。
我本可以是一个竞争者。
In the film 'On the Waterfront', Terry Malloy laments his wasted potential, saying, 'I could have been a contender.'
在电影《码头风云》中，特里·马洛伊哀叹自己浪费的潜力，说道：“我本可以是一个竞争者。”
你能说得更具体些吗？
In 'The Princess Bride', Vizzini repeatedly asks this phrase in frustration during the battle of wits.
在《公主新娘》中，维齐尼在智斗中反复用这句话表达挫败感。
Use could naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
将 could 中的 o 想象成时间环，代表过去的时间，帮助记住它是 can 的过去式。
register: mixed; contexts: 礼貌请求、过去的能力、可能性; note_zh: “could”多用于礼貌请求和可能性表达，语气较委婉。
could 后接不带 to 的动词原形；它既可作 can 的过去式，也可独立表达委婉或较弱的可能性。
Dictionary facts from BRIDGEDICT_CURATED_MODAL, CEFR_J.