Once its impurities had settled, the oil could be graded...一旦杂质沉淀下去，油就可以分级了。The separation and determination of the primary impurities of diflubenzuron by liquid chromatography were carried out.通过反相液相色谱方法往甲醇与水的混合流动相中加入适当...
Once its impurities had settled, the oil could be graded.一旦杂质沉淀下去，油就可以分级了。A filter will remove most impurities found in water.过滤器会滤掉水中的大部分杂质。Oil is refined to remove naturally occurring impurities.油经过提炼去除天然存在的杂质。...
With the gloom of the contraltos added , one could scarcely help shuddering.紧接着是忧郁的女低音, 谁都禁不住直打寒战.Female singers are classified as sopranos, mezzo - sopranos and contraltos.女歌手分为女高音 、 女低音和女中音....
Normally, the seller is obligated to prepay the ocean freight.通常情况下, 卖方有义务预付海运费.prepay a letter预付回信邮费Q 3: What are the treatments prepay?问: 哪些护理是拥有折扣优惠的?Buyer to prepay all shipping, handling, and insurance costs.买方预付所有运...