The correct verb form for the sentence 'Ellos bailaron toda la noche' is 'bailaron.'
The correct verb form for the sentence 'Ellos bailaron toda la noche' is:
In this sentence, 'Ellos' is the subject which means 'They' in English. The correct verb form that agrees with 'Ellos' (They) is 'bailaron' which means 'danced' in English.