"We have plenty of vegetables."
Translation:Nous avons plein de légumes.
"Nous avons plein de légumes." is the preferred translation here but I have never seen "plein de" in any of what have read or studied for "plenty". Instead I see "beaucoup de" as the only way to say "plenty". Shouldn't the preferred translation be "Nous avons beaucoup de légumes."?
neither is to be preferred, they are both correct, although "plein de" is much more informal. They should both be accepted here, anyway
Indeed "beaucoup de" is accepted, as well as other variants, like: "de nombreux/des tas de/des masses de".
Note that "des tas de" and "des masses de" are as informal as "plein de", whereas "beaucoup de" or "de nombreux" are standard.
"on a assez de légumes" - Is this also ok? Or what's wrong with it?
On a assez de légumes = We have enough vegetables (sufficient quantity)
We have plenty of vegetables = Nous avons plein de légumes (large quantity)