空气中所含的氮的比例是多少?What is the percentage of nitrogen in air?作物收获后, 他测定了作物中氮的含量.After harvesting the crops , he tested them for nitrogen content.不含碱性氮的化合物包括吡咯 、 吲哚 、 咔唑和苯咔唑.Non - basic nitrogen - containing series include pyr...
混凝土由距工地大约2英里的分批拌合厂供给.Concrete was supplied from a batching plant located approximately two miles.这种拌合料灌入合适的模框中,振捣压实, 让它硬化.This mixture is placed into a suitable mould, compacted, and allowed to harden.这种染料容易拌合.The paint ...