He swallowed hard.
"How on earth did you know that ?" he asked as soon as he could say anything.
"Oh, it was simple enough.

I didn't really know; I only guessed.

You weren't a real lightkeeper, that was plain.

And you weren't used to washing dishes or doing housework--that," with the irrepressible curl of the corners of her lips, "was just as plain.

When you told me that fib about meeting my brother here last summer I was sure you had met him somewhere, probably at college.