With a determiner:All parents received ______ school calendar by

With a determiner:
All parents received ______ school calendar by mail.
【正确答案】：a
【题目解析】：考查Conversion（转化法）。School名词，（中、小）学校；上课（或上学）时间；此处转化为形容词，a school calendar译为“校历；校日程表”。