"The boy sang a pretty song."

Translation: El niño cantó una canción bonita.

[kRYSa17]

Is it possible to use "un cnanto bonito"?

[RyagonIV]

Canto, when referring to something musical, is more the act of singing, not what you sing. The artful combination of music and words is called canción.

[Anna.Copeland]

Can someone please tell me why Duo's translation is "un tema bonito" instead of "cancion" or "canto"?

[RyagonIV]

Duolingo's preferred translation uses "una canción bonita". If you wrote something with un, Duo will likely choose the masculine term tema as a correction. Canto is less a song, and more the act of singing.

[HowardCJones]

Why can't I use Linda in place of bonita?

[RyagonIV]

Howard, "canción linda" should be okay as well. Please report it if it's not accepted.

[earlvenne]

why isnt it cante instead of canto

[NicholasM.15]

"Canté" -> "I sang"

"Cantó" -> "he/she/you sang" (Note the accent! It makes a big difference between first person singular present tense and third person and second person formal singular past tense)

In this case, "el niño" is third person singular, hence "cantó".

(sorry for cluttering your email! There's no way to edit it on the app. I had to delete this two times to edit it)