HEY THERE.
THE ANSWER IS
Imparfait = what was happening all around you (including you), background. Also ongoing events, habits, what used to be.
Passé composé = what took place at that very moment: a specific event or a succession of specific events, the main storyline.
It depends on what you want to say, I can translate for you on what you want to say if you want?
Answer:
1- Je regarde la télévision à seize heures vingt cinq
3- Elle enseigne à huit heures quinze
4- Tu écoutes la radio à douze heure pile / midi
