Task: Question Generation
Input (English): Context : The 2015 Singapore Grand Prix (formally known as the 2015 Formula 1 Singapore Airlines Singapore Grand Prix) was a Formula One motor race held on 20 September 2015 at the Marina Bay Street Circuit in Marina Bay, Singapore. 
Subject : 2015 Singapore Grand Prix 
Relation : point in time
Output (English): When did 2015 Singapore Grand Prix occur?