基本解释放牧蜂群英汉例句双语例句Not until the 1920s when cars and trucks became affordable and roads improved, did migratory beekeeping begin to catch on.直到19世纪20年代当汽车和卡车比较经济和道路改善， 迁移养蜂开始流行。词组短语短语beekeeping migratory 转地放蜂