Подставка для для различных предметов или диван с креслом возможно это какая нибудь горка
In это дляслучаяев когда имеется ввиду внутри чего-то, а at - когда возле или около, или во время например
1. B: Oh, I have already seen it twice.
2. A: Do you know that Mrs Jones has been working here for sixteen years?
B: I thought she started working here ten years ago.
3. A: Have you ever met anyone famous?
B: Yes, last summer I sat next to Brad Pitt on a plane to LA.
4. A: How long ago did you start painting?
B: I have recently completed a painting that the Nationall Gallery asked me to do a year ago.