Answer:
Donde estudian Isabel y sus amigas?
Explanation:
Instead of saying where they study(which is in the library) you would ask where they study. Sorry if I'm too late.
Well, if you want the answer for "I would tell them to know what they want to do before going to college", then it's " Les diría que sepan lo que quieren hacer antes de ir a la universidad "
2. estuviera
3.vieran y fueran
