防汛: flood prevention [control]: 防汛大军 an army of flood-fighters◇防汛指挥部 flood-control headquarters
大军: 1.(主力部队) main forces; (huge) army 短语和例子大军过处, 秋毫无犯。 wherever the troops went, they never infringed on the people's interests. 我们是先头部队, 大军随后就到。 we are the advance detachment. the main forces