Câu "Could I borrow your pen?" sẽ mang sắc thái lịch sự hơn hẳn câu "Can I borrow your pen?", dù chỉ khác một từ.
|I want another hamburger.
||I'd like another hamburger.
||Could you repeat that, please?
||I think you might be mistaken.
|Hey, where's the bathroom?
||Excuse me, could you tell me where the bathroom is?
|Do this today.
||It would be great if you could do this today.
|Who are you?
||May/Could I ask/have your name?
|Can I borrow your pen?
||Could I borrow your pen?
|Can I say something?
||Can I just say something here, please?
Theo 7 ESL