以正庚醛 、 硫代硫酸钠和溴代正丁烷为原料,合成了正庚醛正丁硫醇缩醛.The heptanal butyl mercaptan was synthesized with heptanal, sodium thiosulfate and 1 bromobutane as raw materials.目的研究以庚醛和原甲酸三乙酯为原料制备庚醛二乙缩醛的工艺条件.Aim Enanthal diethyl acetal is prepared ...
For hundreds of years, St Bernard dogs have saved the lives of travellers corssing the dangerous pass.几百年来, 圣·伯纳德的狗挽救了许多穿越这个危险关隘旅行者的生命.The famous monastery of St Bernard , which was founded in the elventh century, lies a...
He gave Dixon a mutinous glare.他朝狄克逊恶狠狠地盯了一眼.Excuse me, Mr Dixon, have you got a minute to spare.对不起, 狄克逊先生, 您能耽误一分钟吗.Indiana had a history of bigotry unequaled north of the Mason - Dixon line.印地安纳州的种族偏见的历史在 梅森——迪克森 线以北是...
His contribution is immeasurable.他居功至伟。to make a contribution to charity给慈善事业捐款Her contribution to the research went largely unacknowledged.她对这项研究的贡献大都被忽略了。...