词汇	evolution of petroleum
释义	evolution of petroleum 石油的形成
随便看	system of rotating axes system of rotating green manure crops system of rule by law system of rules system of running a school system of running school system of running schools system of rural land system of safety management system of salary allotment system of school education system of schooling districts system of school management System of science andtechnology system of science and technology system of scientific auditing system of scientific knowledge system of scientific research allowance system of sea cooling water system of secondary elevator System of secret voting system of segment connecting device system of selecting courses system of selecting lessons system of selection