When we had finished talking, my sister stood up and went to the door. At the door she stopped and looked at me.

She said: "Did you hear anyone whistling in the middle of the night?"

I said: "No, I didn't; why?"

She answered: "On the last three nights I've always heard a whistle at about 3a.m., but I don't know if it came from the next room or from the garden. I thought the best thing was to ask you. Do you whistle when you sleep?"

"I'm sure I don't, and I've never heard a whistle" ....

"Yes, it's not important anyway"

My sister went away. Later I heard her key turning in the lock. We used to lock the doors of our rooms during the night, because we were a bit afraid of the big animals around the house. Then I went to bed.