Firefighting is an inherently dangerous occupation.消防工作本身是一项危险的职业.Here, Elvis the heavy - duty, - engine helitanker shows off its firefighting skills for the Oshkosh crowd.在这里, 猫王的重型双引擎直升机,空中加油机炫耀的奥什科什人群的消防技能.Scope of ap...
Incorporating organic material into chalky soils will reduce the alkalinity.在白垩质土壤中添加有机物可降低其碱性。Some soils are actually too alkaline for certain plant life.有些土壤其实碱性过强，不利于某些植物生长。Rye is tolerant of poor, acid soils.黑麦耐贫瘠的酸性...
140号藏品特别引入注目,因为它是由整块软玉雕琢而成.Made of a single piece of nephrite, Lot 140 was remarkable.两种不同的矿物称为玉, 硬玉和软玉.Two different minerals are known as jade, jadeite and nephrite.摘要青海软玉矿床产于中酸性侵入岩与大理岩接触带中.Nephrite deposits in Qinghai...