媒體英語(yǔ)會(huì)帶大家一起學(xué)習(xí)BBC撰稿人在報(bào)道世界大事時(shí)常用到的單詞和短語(yǔ)。

Background: 科學(xué)家最新發(fā)現(xiàn)了兩億五千年前類似恐龍的動(dòng)物足跡。這一發(fā)現(xiàn)將恐龍存活的年代提早了幾百萬(wàn)年。

These earliest dinosaur-like animals were about the size of domestic cats. They would have weighed two or three pounds (1 to 1.5 kilos) and walked on four legs.

But what's really intrigued scientists is that they date from two million years after the worst mass extinction event in the history of the planet.

It was a time when volcanic eruptions, sudden global warming and a stagnation of the oceans wiped out more than 90% of all life on Earth.

Up until recently scientists thought that dinosaurs emerged 15 to 20 million years after this event. But the new footprints suggest that they arose directly as a result of the devastation, filling a gaping ecological void. Without the mass extinctions there would have been no dinosaurs.