托福听力短文 II-01-1

(WA-MM) Not long ago, some of you may have read about a team of mountain-climbing scientists who helped to recalculate the elevation¹ of the highest mountain in the world: Mt. Everest. Of course, the elevation of Mt. Everest was determined² many years ago, using traditional surveying methods. But these scientists wanted to make a more precise measurement using a new method that takes advantage of recent advances in technology. It's called the Global Positioning System.

The Global Positioning System uses 24 satellites that circle the Earth. Each of these satellites is constantly sending out signals. And each signal contains important information that can be used to determine the longitude³, latitude⁴, and elevation of any point on the Earth's surface.

Well, in order to use this system to calculate Mt. Everest's elevation, scientists needed to put a special receiver on its summit to receive signals from the satellites. The problem with this was that, in the past, the receivers were much too heavy for climbers to carry. But now these receivers have been reduced to about the size and weight of a handheld telephone, so climbers were able to take a receiver to the top of Everest and, from there, to access the satellite system signals that would allow them to determine the precise elevation. And it turns out that the famous peak is actually a few feet higher than was previously⁵ thought.

1 elevation   

n.高度；海拔；高地；上升；提高

参考例句：

• The house is at an elevation of 2,000 metres.那幢房子位于海拔两千米的高处。
• His elevation to the position of General Manager was announced yesterday.昨天宣布他晋升总经理职位。

2 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

3 longitude   

n.经线，经度

参考例句：

• The city is at longitude 21°east.这个城市位于东经21度。
• He noted the latitude and longitude,then made a mark on the admiralty chart.他记下纬度和经度，然后在航海图上做了个标记。

4 latitude   

n.纬度，行动或言论的自由(范围)，(pl.)地区

参考例句：

• The latitude of the island is 20 degrees south.该岛的纬度是南纬20度。
• The two cities are at approximately the same latitude.这两个城市差不多位于同一纬度上。

5 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。