Consider the following quote, please:
“You don't know what can happen tomorrow. Life is like a novel, isn't it? It's filled with suspense. You never know what's going to happen until you turn the page.” ― Sidney Sheldon (a well-known American writer)
In the bold sentence, wouldn't could be a better choice than can? To me, can is definite here and so doesn't sound good, while could in the sense of "maybe will" sounds better.