"Constantin drove me to the UN is his old green convertible"

A 'convertible' is a car with a retractable top, so that it can be used with the roof either 'up' or 'down'.

Convertibles may be 'hard top' or 'soft top': 'hard tops' have roofs made out of metal, plastic, or carbon fibre; 'soft tops' have roofs made out of vinyl, canvas, or other textiles.

'An old green convertible'
Public Domain'An old green convertible' - Credit: CZmarlin, Wikimedia Commons