Fire and water do not agree.
What does `do not agree' means here?
I have no context, it is an example of subject verb agreement chapter in my grammar book.
Even further than that - water will extinguish fire - so they cannot get along together.
I guess what puzzles you, Gary, is that other meaning of agree - be in harmony with; suit.
Why can't your children agree?= Why can't they get on well?
Such a climate does not agree with me.
The meat I ate for lunch hasn't agreed with me.