常见例句双语例句Bromacil was synthesized using 2-bromobutane and urea as the starting materials in three steps including condensation, cyclization and bromination with total yield of 61%.以2-溴丁烷和尿素作为起始原料，经缩合、环化、溴代三步反应得到除草定，总收率为61%。 返回 bromobutane