英语听力文摘 English Digest 154、火星上的海洋

　　Don: Hey, Yael, Have you heard? We've discovered two new oceans?
Yael: Where?
D: On Mars. Well, they aren't there any longer, but they were there a few billion years ago.
Y: I thought scientists weren't sure if Mars had oceans or not.
D: They weren't. The Mars Opportunity Rover found sulfates and other salts in the soil that were left behind when standing¹ water evaporated. It also discovered cross-bedding in the soil which was created by water ripples², and tiny mineral deposits  called blueberries that only appear if water is present. The northern lowlands of Mars looked like there might have been an ocean there, but there wasn't definite proof.
Y: So, what has changed their minds?
D: Gamma Ray evidence.
Y: That sounds exciting.
D: It is. The Mars Odyssey³ spacecraft had a gamma-ray spectrometer onboard that  could detect elements buried as much as a third of a meter, or thirteen inches, below  the soil. Scientists used the spectrometer to measure the amount of potassium, thorium, and iron above and below what they thought to be the shoreline of ancient   oceans. They expected to see low concentrations above the shoreline and larger concentrations below. That would indicate that the elements had been leached⁴ out of the soil by the water.
Y: So, what did they find?
D: They found the shorelines of a younger ocean about ten times the size of the Mediterranean⁵ Sea, and an older ocean twice that size.
Y: It's too bad those oceans still aren't there.
D: Yeah. It sure would be a great spot for a cruise.

1 standing   

n.持续，地位；adj.永久的，不动的，直立的，不流动的

参考例句：

• After the earthquake only a few houses were left standing.地震过后只有几幢房屋还立着。
• They're standing out against any change in the law.他们坚决反对对法律做任何修改。

2 ripples   

逐渐扩散的感觉( ripple的名词复数 )

参考例句：

• The moon danced on the ripples. 月亮在涟漪上舞动。
• The sea leaves ripples on the sand. 海水在沙滩上留下了波痕。

3 odyssey   

n.长途冒险旅行；一连串的冒险

参考例句：

• The march to Travnik was the final stretch of a 16-hour odyssey.去特拉夫尼克的这段路是长达16小时艰险旅行的最后一程。
• His odyssey of passion, friendship,love,and revenge was now finished.他的热情、友谊、爱情和复仇的漫长历程，到此结束了。

4 leached   

v.（将化学品、矿物质等）过滤( leach的过去式和过去分词 )；（液体）过滤，滤去

参考例句：

• They believe that the humic materials are leached from decaying plant materials. 他们认为腐植物料是从腐烂的植物体浸沥而来。 来自辞典例句
• The concept holds that uranium is leached by groundwater from tuffeceous rocks. 该理论认为，来自凝灰岩的地下水淋蚀铀。 来自辞典例句

5 Mediterranean   

adj.地中海的；地中海沿岸的

参考例句：

• The houses are Mediterranean in character.这些房子都属地中海风格。
• Gibraltar is the key to the Mediterranean.直布罗陀是地中海的要冲。