BBC news 2009-10-12 加文本

1.Scientists have warned of an alarming increase in the extinction of animal species because of the threats to biodiversity and ecosystems posed by pollution, climate change and the spread of cities.

参考翻译：科学家提出警告，由于环境污染，气候变化和城市的扩散对生物多样性和生态系统造成的威胁，动物物种大量灭绝。

结构分析：这句话的主干是Scientists have warned of an alarming increase。in the extinction of animal species补充说明是什么的增加。because of说明物种灭绝增加的原因。posed by说明威胁的施加者。

2.The Diversitas Group, rather, of global experts on biodiversity said it’s appeared increasingly likely that reduction targets set by world leaders for 2010 would not be met.

参考翻译：来自Diversitas Group组织的全球生物多样性专家称，世界领导设立的2010年生物物种减少的目标极有可能不会实现。

结构分析：在这里it是形式主语，真正的主语是后面that引导的从句。

3.The head of the United Nations mission in Afghanistan has appeared at a news conference flanked by the American, British and French ambassadors in what’s being seen as an international show of support for him.

参考翻译：在美国，英国和法国大使的陪同下，联合国阿富汗特派团代表卡伊·艾德(Kai Eide)参加了新闻发布会。这场新闻发布会被视为国际社会对他的支持。

结构分析：这句话的主干是The head of the United Nations mission in Afghanistan has appeared at a news conference。flanked by过去分词作伴随状语。what’s being seen as是what引导的名词性从句做in的宾语。