• on OR in OR at?

A:  Listen – is this right: ‘I live on 99 Bishan Road’?

B:  No, that’s wrong! You live in 99 Bishan Road.

C:  Both wrong! You live at 99 Bishan Road.

Who is right? In is generally used when we talk about a location ‘inside’ something (in the house, in the theatre). On is used for a location ‘on top of’ something (on the table, on the floor), and at is used for a location which is a point on a horizontal or vertical surface (at the end of the drive, at the window). The problem is that there are different ways of looking at the same location.

But C is right.

At is used when street numbers are mentioned because we think of a particular point along the street, namely No. 99.