Questions & Answers about Ya es de noche, ¡que descanses bien!
Why do we say que descanses instead of just descansa?
Using que followed by the subjunctive (like descanses) is a very common way to express a wish or hope for someone else. It is actually a shortened version of espero que descanses (I hope that you rest). While descansa is a direct command telling someone to rest, que descanses bien is a warm wish meaning "I hope you rest well."
Why does descansar end in -es here? I thought tú forms for "-ar" verbs ended in -as.
That is the present subjunctive at work! Because you are expressing a wish (triggered by que), the verb changes to the subjunctive mood. For regular "-ar" verbs like descansar, the tú ending swaps to -es, making it descanses.
Why is it es de noche and not está de noche? Doesn't the time of day change?
Even though day and night are temporary states, Spanish always uses ser to talk about the time and parts of the day. The phrase es de noche is the fixed, standard way to say "it is nighttime" or "it is dark out."
What exactly does ya add to the beginning of the sentence?