“Can" and “could" are both modal verbs that are used to express possibility or ability.
“Can" is used to express that someone has the ability to do something, or that something is possible. It can be used to ask for permission, to offer help, or to request that someone do something. For example:
- Can you help me with this? 你能幫我這個嗎？
- I can speak Spanish. 我能說西班牙語。
- Can I borrow your pen? 我能借你的筆嗎？
“Could" is used to express a possibility or to make a request in a more polite or formal way. It is often used to express past ability or to ask for permission in the past. For example:
- Could you pass the salt, please? 請問能給我鹽嗎？
- I could swim when I was younger. 我年輕時能游泳。
- Could I have a glass of water? 能給我一杯水嗎？
In general, “can" is more common in spoken English, while “could" is more common in written English. However, both forms can be used in either context.
一般來說，"can" 在口語中更常用，而 “could" 在書面語中更常用。但是，兩種形式都可以在任何情境中使用。