question: When was Nanjing announced as the host city for the 2nd Summer Youth Olympic Games ?
answer: 10 February 2010
turker_answer: Nanjing was announced as the host city for the 2nd Summer Youth Olympic Games on 10 February , 2010 .
rule-based: Nanjing was announced as the host city for the 2nd Summer Youth Olympic Games in 10 February 2010 .