"The carrot is good for soup."

[violeta877655]

I think ”pentru” works as well. ”Morcovul e bun pentru supă”. ”Pe” and ”ca” definitely not work in this sentence.

[zj456]

Why "la" and not "pentru"? Or even "pe" or "ca"?

[Caesar_Imperator]

None really work here. I would just learn it as it is.