Complex sentence: The concession of Autostrada A31 was originally expired on 30 June 2013, which was agreed in 1999, after that the company started to construct the extension from Vicenza to Rovigo in the south in 2005.
Split into simpler sentences: The concession of Autostrada A31 was originally expired on 30 June 2013, which was agreed in 1999. After that the company started to construct the extension from Vicenza to Rovigo in the south in 2005.