科技英语课外练习译成汉语版.doc

P23 1.Thunderstorms producing large hail are also likely to produce tornadoes. 2.Contrary to the opinions of many people , tornadoes are not particularly energetic. 3.An average tornado contains much less energy than the thunderstorm that produces it, and is appreciably less energetic than a cyclone. 4.But since the energy of a tornado is expended in a short period of time, its power-energy divided by time is relatively high. 5.Because of their concentrated power, tornadoes are probably the most feared of all weather phenomena. 6.They often strike suddenly, with little warming, and in a few minutes cause extensive damage to property, injuries and loss of lives. 7.Tornado may have the appearance of a narrow funnel, cylinder, or rope extending from the base of a thunderstorm to the ground. 8.The visible funnel consists mostly of water droplets formed by condensation in the funnel. 9. Near the ground blowing dust, leaves and other debris identify the presence of a strong vortex. 10.Tornadoes and weak visible vortex observed over water-most often in the tropics and subtropics are called water spouts. 较大冰雹的雷暴也很有可能会形成龙卷风。许多人持相反的态度，认为龙卷风不会有特别的能量，一般的龙卷风形成的能量要比雷暴产生的能量要少，也比气旋的能量要略小一些，但是，因为龙卷风的能量在短时间内有所消耗，其单位时间内的能量相对要高。由于龙卷风的能量较为集中，它们很可能是最为恐惧的天气现象，龙卷风常常在毫无征兆的情况下突然袭击，在数分钟内造成巨大的财产损失和人员伤亡，龙卷风可能会以狭小的漏斗、圆柱成绳索形状出现，以雷卷为雏形从地面形成水滴构成地面附近尘土、树叶和其它碎片飞扬，形成更大的涡流，龙卷风以及依稀可见的水上的涡旋称之为水龙卷，主要在热带和亚热带出现。可见的漏斗装的是由凝聚在漏斗里的水滴组成。 P58课外练习： 1. Fog can pose a serious hazard to both surface and air travel. 2. Many auto accidents and ship collisions and aircraft crashes have been attributed, at least in part to visibility restrictions caused by dense fog. 3. Fog frequently forces flight delays, reroutings and cancellations that cost airlines millions of dollars each year and inconveniences for thousands of passengers. 4. Although the need for an effective method of fog dispersal is great, especially at airports, little progress has been made in this area for both technical and economic reason. 5. During