freeing formula是什么意思

用法例句

The principle and ingredients of drain deoppilants are introduced with a view of the latest development of its solid and liquid types in China.

概述了下水道疏通剂的疏通原理及各组分的作用,综述了近年来建筑物下水管道固体疏通剂和液体疏通剂的国内开发情况。