Look at the picture.
A table is in the middle.
1. A chair is on the right.
2. A chair is at the right.
3. A chir is on the right of the table.
4. A cahir is at the right of the table.
(Which preposition do we have to sue? Which ones are grammatical?)
1 answer
"on" is the better of these two prepositions to use in these sentences. "at" is not incorrect, but "on" is simply smoother.