Questions & Answers about Je vais préparer le décor dans trois heures.
Why do we use dans here instead of en for "in"?
In French, dans followed by a time expression means that an action will happen "in [amount of time] from now." Because you will start the preparation three hours from the present moment, you must use dans. If you wanted to say that the preparation itself takes three hours to complete, you would use en (en trois heures).
Does le décor always mean "the set" like in a theater?
Why use Je vais préparer instead of a single future tense word like préparerai?
Je vais préparer is the near future tense, made by combining the present tense of aller (to go) and the infinitive préparer. It translates directly to "I am going to prepare." French speakers use this very frequently for planned actions in the relatively near future, which fits perfectly with the specific, upcoming timeframe of dans trois heures.
How do I pronounce trois heures? Is there a liaison?