sentences:  The number 2 car was driven by Ayrton Senna until he was killed at Imola.Williams test driver David Coulthard filled in for most of the season but Williams also brought back Nigel Mansell, who had won them the drivers' title for them in 1992, when his Indycar commitments allowed.Although it was fast, the car proved to be a tricky proposition in early testing and in the early part of the season.