单选题 Jack said the construction of the subway would be completed in October, ______ is a great surprise to us.
【正确答案】 D
【答案解析】[解析] 本题考查非限制定语从句的引导词。空格前的逗号说明，空格应为引出非限制性定语从句的引导词。四个选项中只有选项D可作非限制性定语从句的引导词，故为正确答案。