课件例句.docVIP

课件例句 1. A long metal bar is fixed in a resort stand by one end. The other end is heated in a flame until it becomes red. The bar and the stand are then moved away from the heat. The temperature of the hot end of the bar is found to fall rapidly. 2. The limitation of physical model techniques share, in other branches of engineering, led to the development of mathematical models representing a variety of mechanical structures. The development of the analytical approach has accelerated since the introduction of large digital and analogue computer installations. 3. What is really required therefore is a safe, reliable and inexpensive device, which can be inserted between the transmission line and the consuming apparatus, to convert the high voltage and low current of the economical transmission line into the low voltage and high current required by the consuming apparatus, that is, a piece of apparatus to perform the same function in electrical transmission that a pair of reduction gears does in mechanical transmission, in which a high torque and low speed are readily and effectively converted into a low torque and high speed, or vice versa. 因此，在输电线路和用电设备之间，的确需要一种可以将经济的输电线路的高压小电流安全可靠，成本低廉地转换成用电设备所低压大电流的装置，也就是说，在电力传输中，需要一种和在机械传动中用来方便高效地将低速大转矩转变成高速小转矩或将高速小转矩转变成低速大转矩的齿轮传动起着相同作用的装置。 4. Modern natural history is exacting science, whose practitioners must also cope and improvise in different field conditions. 现代自然史是一个需要付出极大努力的学科，不仅如此，其研究者还要想办法克服野外环境带来的困难。 5. These include birds, carnivores, primates and large game. 这些包括鸟类，肉食动物，灵长类动物和大型猎物。 6. A new device is put in the chimney. 一种新的装置装入了烟囱。 7. Friction can be reduced by lubrication. 润滑能减少摩擦。 8. They are especially interested in finding cures for illness which western medicine has found incurable. 9. The individual then exhaled into a Spiro meter which measures volume and rate of air exhalation. 10. The arteries and veins do not allow anything to pass though their walls, but the 11. Hardened vessel walls cause a rise in