英语听力:自然百科 金星和水星旅行指南 Venus and Mercury-3(在线收听

 Craters here stretch as far as the eye can see. Although no human has ever set foot on Mercury, we have a pretty good idea of what you would see.

 
If you are walking around on the surface of Mercury, it will look outwardly a lot like the moon.
 
When you step onto Mercury, you step into a world with no real atmosphere where the sky is as black as night and ablaze in \ sunshine, and where a drive is an off-road track through at least a 3-billion-year-old battlefield.
 
Big craters, small craters, craters everywhere. So, that's your first impression looking at it.
 
Like the moon, Mercury took most of its battering early on. A silent witness to the dawn of time, it's been undisturbed by a single drop of rain or breath of wind ever since.
 
For the most part, the surface of Mercury has been frozen in time for periods of billions of years. And you may say that's boring, ah, but unnecessarily it's a good thing, because these planets such as Mercury and the Moon preserve a record of what was going on during this critical early period of the solar system's formation and so we can basically study it there because it's lying right \ on the surface.
 
Every stone and crater\ of this pockmark world has the potential to gaze back 4.5 billion years. But counting these craters is just the first challenge when it comes to revealing a planet like Mercury.
 
It's always low on the horizon so it's hard to point a telescope at it from earth. It's hard to get into an orbit around Mercury because it's so close to the sun.
 
For that reason, Mercury remains one of the most under-explored planets in our solar system
  原文地址:http://www.tingroom.com/lesson/zrbaike/2012/260548.html