"I don't know when the concert is."
Translation:No sé cuándo es el concierto.
That's a good word order for this type of question:
Interrogative + verb + subject.
¿Cuándo + es + el concierto?
¿Dónde está tu hermana?
¿Cuál es su abrigo?
¿Dónde viven los García?
You can keep this word order when you include the question in another sentence, like they did above.
Also notice that the English word order has subject + verb: .............the concert is.
I am sure this is a dumb question, but here goes: I got the answer correct "No sé cuándo es el concierto", but wanted to know why in this type of sentence both saber and ser are conjugated?
Not a dumb question. :) When two verbs appear in a row, only the first in conjugated. When they are part of separate clauses within one sentence, they are treated separately. Complex sentences, therefore, may wind up with many conjugated verbs or many combinations of conjugated and infinitive verbs. It's very much like English in this. Take an example using the infinitive verbs "to want" and "to be":
- She wants to be an astronaut.
"To want" is conjugated to "she," but "to be" is left alone. Now add some additional clauses:
- She wants to be an astronaut but she is still too young.
The second "to be" is conjugated. This would be the same in Spanish:
- Ella quiere ser astronauta pero aún es demasiado joven.