Methods: The synthesis uses urea as material process includes condensation, opening loop, chloridization and nitrosation reaction. 方法以尿素为原料,经缩合, 开环, 氯化,亚硝化而得.
他们试着在洞穴正下方的一块地上挖掘。They tried digging in a patch just below the cave.这正是洞穴探险者害怕的那种洪水。This is the type of flood dreaded by cavers.那些洞穴深约18公里。The caves extend for some 18 kilo-metres....
不要靠近那个变压器.Keep away from the transformer.变压器可在两个晶体管之间隔离直流 偏压.The transformer isolates the transistors with regard to d - c bias voltage .降压变压器 的匝数比小于1.A step - down transformer has a turns ratio less than 1....
屋顶的两面斜面都有破瓦片.On both slopes of the roof there are broken tiles.伽利略让小金属球从斜面滚下.Galileo rolled small metal balls down the incline.图3.21画出了平行于斜面的、相互保持平衡的几个力.Figure 3.21 shows the forces parallel to the plane that are respons...