question: Where were the 18th and 19th satellites for the BeiDou system launched from ?
answer: the Xichang Satellite Launch Center
turker_answer: The 18th and 19th satellites for the BeiDou system were launched from the Xichang Satellite Launch Center .
rule-based: The 18th and 19th satellites for the BeiDou system were launched from the Xichang Satellite Launch Center .