Maybe it was the fish or meat we ate.
Yes, it might have been.
Or the soup.
No, it couldn't have been the soup because I didn't have any.
Of course. We sat in the sun for a long time. I suppose it could have been the sun.
Yes, it might have been. But we've got used to sitting in the sun.
That's true. Now what else did we both eat? Only those lovely pears I bought. It couldn't have been them. We're used to eating pears and you washed them.
No, I didn't. I thought you had.