O que significa "cair duros" em inglês?

It's an expression... in this case it means "to die (quickly)", but it also indicates surprise.

=> O velho CAIU DURO enquanto cuidava do jardim. (he died)
=> Você vai CAIR DURO quando vir a nova versão do Windows. (you'll be surprised to see it)

Excellent, thank you very much!

I'm going to add the sentences you gave me as examples. I'll translate them into English, to see whether I understood them correctly:

O velho CAIU DURO enquanto cuidava do jardim. (he died)
The old man died when he was taking care of the garden.


Você vai CAIR DURO quando vir a nova versão do Windows. (you'll be surprised to see it)
You are going to be surprised when you'll see the new version of Windows.

Great!

=> O velho CAIU DURO enquanto cuidava do jardim. (he died)
=> The old man died WHEN HE WAS taking care of the garden.

"Quando" means "when", "enquanto" means "while"... Maybe "while taking care..." is better.

Excellent!
I was just going to ask you about the difference between those two words.

And what did you think about my rendition of your sentence about the "sudden" death any minute? :) Would you change anything there?

What do you think about "to die at a moment's notice"?

I think it's a bit poetic :)
I'm not sure it's exact in this case, although it *can* be a suitable variant. Do you think I can leave my own version (and you'll add yours), or would you change it to yours, "to die at a moment's notice"?

It depends whether you feel that the "de um instante para o outro" was properly conveyed in my version, or not.

Ohh, just keep your version! I think it's good enough! :)