"I didn't know if I was going yesterday," Hermione said again, as patiently as she could. "And I didn't want to bring it up if I wasn't going to go." With good reason, as it seemed. "I really am sorry that I ruined your plans, and I told you, I'll stay. My parents will understand."
Shrugging, she ran a hand through her hair. It was no use responding to Ron as he told her he might decide to leave for three days and not tell her, and Hermione was fairly sure she would let him know about any plans she ever had so he would have known beforehand.
When it came to his last question though, "Both?" she suggested with a sigh.