Here are the sentences completed with appropriate prepositions based on the context:
1. Today the sun is shining in the sky, the sky is bright and clear.
2. Where are you in this family photo?
3. In the evening I like to sit by the window and read a book.
4. We can often see flowers on the piano in the living room.
5. The bank on High Street is big and modern.
6. You can sit in this comfortable armchair when you watch television.
7. The birds on the tree are not sparrows. What kind of birds are they?