Original sentence: The construction was started on 10/10/2011 and orginally expected to finish in 2015, and construction was completed in September 2018, and then the pilot run and testing was conducted for 3 to 6 months
Edited sentence: The construction was started on 10/10/2011 and orginally expected to finish in 2015, but finally the whole construction was completed on September 2018, and then the pilot run and testing was conducted for 3 to 6 months