"Nos gustaron esas flores."
Translation:We liked those flowers.
Just for fun, and to help my brain get a better handle on the way gustar works, I translated this literally and wrote" The flowers pleased us", rather than we liked the flowers. Duolingo marked it wrong. Just in case you were thinking of trying it.
I don't understand this. Nos = we, but gustaron = they liked. Is what I'm saying incorrect?
It's the flowers that are the subject of the sentence. The drop down translation is misleading. It's more like "Those flowers pleased us" so gustar is conjugated for the flowers.
"Gustaron" is past tense -- 3rd person plural. It agrees with the flowers. Sentences about someone liking something have to be constructed this way: the flowers were pleasing to us = to us were pleasing the flowers = we liked the flowers.