By Jonathan Amos, BBC News

媒体英语会带大家一起学习BBC撰稿人在报道世界大事时常用到的单词和短语。

Background:土卫六是土星最大的卫星，它主要是由水、冰和山脉组成。科学家近日在旧金山召开的美国地球物理学联合会上宣称他们可能在土卫六上发现了冰火山。

Titan shroudedis a mysterious world. Because it's shrouded in a thick, oily haze, it's extremely hard to identify anything at the moon with confidence. But with temperatures that plunge to minus 180 Celsius at the surface, researchers had suspected it might have ice volcanoes.

And now the Cassini probe has spotted a 1,500m-high mountain with a deep pit in it, and what looks like a flow of material nearby.

Scientists can only speculate what sort of material a cryo-volcano might erupt, but the complexchemistry at Titan suggests it could be a slushy water-ice containing ammonia.

If there are a lot of carbonmolecules present, the lava could even look like softened asphalt, candle wax or even polyethylene.

The team which discovered the mountain have dubbed it "The Rose".

• mysterious [mi´stiəriəs]   a.神秘的；难以理解的   (初中英语单词)
• extremely [ik´stri:mli]   ad.极端地；非常地   (初中英语单词)
• identify [ai´dentifai]   vt.认出；鉴定；验明   (初中英语单词)
• plunge [plʌndʒ]   v.插进 n.投入；冲击   (初中英语单词)
• complex [´kɔmpleks]   a.复杂的 n.综合企业   (初中英语单词)
• chemistry [´kemistri]   n.化学   (初中英语单词)
• carbon [´kɑ:bən]   n.碳；(一张)复写纸   (初中英语单词)
• asphalt [´æsfælt]   n.沥青   (英语四级单词)
• speculate [´spekjuleit]   vi.思索；推测；投机   (英语六级单词)