How would you say mi papa promete llegar a casa temprano in a question?

To turn "mi papá promete llegar a casa temprano" into a question, you could ask, "¿Mi papá promete llegar a casa temprano?" This directly transforms the statement into a question by adding the appropriate punctuation and keeping the structure intact. Alternatively, you could ask, "¿Promete mi papá llegar a casa temprano?" which emphasizes the promise.