Questions & Answers about Nước đã có sẵn.
Yes, nước can mean either water or country/state in Vietnamese, so context matters.
In Nước đã có sẵn, it means water, because the rest of the sentence fits the idea of something being available / ready. In another context, nước could mean country, as in nước Việt Nam (the country of Vietnam).
So this is a good example of a common Vietnamese word whose meaning depends heavily on context.
Đã often marks that something is already true or that a change of state has happened before now.
In Nước đã có sẵn, it gives the sense of:
- The water is already available
- The water has been prepared / made ready
- There is water ready now
So đã is not exactly the same as the English past tense. It often points to completion or already-ness, rather than simply "past time."