氨的合成主要经过四道工序.There are four major steps in ammonia synthesis.试计算氮在尿素及硫酸氨的质量百分率.Calculate the percentage by mass of nitrogen in urea and ammonium sulphate.这种肥料经过化验表明氨的含量很高.Tests of the manure showed a high ammonia content...
He works as a painter and decorator.他的职业是油漆匠和装潢师傅。Moira looked around and sniffed. 'This place badly needs a decorator.'...莫伊拉环顾四周，抽了抽鼻子。“这个地方太需要有人来装修一下了。”Moira looked around and sniffed. "This place badly need...