Martha looked over at him, and took a breath, before looking away again. "Yeah, I know. It's just... hard."
She wanted to go deeper than that, really. Talk about the Doctor and Jack and Rose, and maybe even deeper with the Year That Never Was, but she didn't. Couldn't. Wouldn't. Besides, she'd dealt with that year a long time ago, hadn't she?
Pushing the thought away she looked over at Obi-Wan again, and managed a smile, slight as it was. "Thank you."