绝大多数种类以吃螺为生。Most species live off aquatic snails.它展现了螺杆泵采油系统在高粘稠油和出砂井等方面良好的应用前景。It shows good application future in high viscid oil wells and sand product.涡轮喷气发动机和涡轮螺桨发动机更适用于飞机.The turbojet and the turboprop are much mor...
The Indians chipped flint arrowhead.印第安人凿制燧石箭头.An arrowhead is never used at the radius center.箭头永远不可以指向圆心.Only the arrowhead , carved from some milky blue stone, had any color.只有箭头, 是用乳状的蓝宝石雕刻的, 发出一些色泽....
The production of wear - resistant castables is optimized based on rheology, powder engineering, collochemistry and thermodynamics.耐磨 浇注料是建立在流变学 、 粉体工程学 、 胶体化学、热力学等前沿耐火材料理论基础上充分优化制成....
...the protection of mankind against the forces of nature: epidemics, predators, floods, hurricanes...保护人类抵御自然力——传染病、食肉动物、洪水和飓风During the annual floods the river deposits its silt on the fields.每年河水泛滥时都会在田野上沉积一层淤泥.Foreca...