英语语法分析

Methods Microfilarial rate at various levels was investigated first. Then different dose of hetrazan medicated salt was worked out and sent to farmers.

方法先查清各县（市、区）分乡（镇）微丝蚴率，然后分乡制定出海群生药化食盐的剂量，再按规定剂量送盐到户。