听力原文： The Larsen B ice shelf covered more than 3,000 square kilometers and was 200 metres thick until its northern part disintegrated in the 1990s. Three years ago, the central part also broke up. An international team of researchers used data collected from six sediment cores near the former ice shelf to show the shelf had been relatively intact for at least 10,000 years or since the last ice age. The collapse therefore goes beyond what would be expected naturally at the time. Rather, the demise is likely the result of long-term thinning due to melting from underneath, as well as short-term surface melting from global climate change, the researchers suggest. Then in five years, the shelf shrunk by 5,700 square kilometres, say scientists who found the break up caused changes in currents and species in the area. 'As the ice shelves are disintegrating, the glaciers that are feeding them from the land are surging forward,' said Robert Gilbert, a geography professor at Queen's University in Kingston, Ont. Glaciers are no longer being held back from the ice shelf, and are pushing icebergs into the sea, said Gilbert, one of the co-authors of the study in Thursday's issue of the journal Nature. As the glaciers melt, global sea levels could change more than predicted, he said. Flooding could result in low-lying areas. Scientists are now watching to see if the most southern part of the Larsen ice shelf, the coldest part of Antarctica. is going to break up. The Larsen B ice shelf covered more than 3,000 square kilometers and was (36) meters thick until its northern part (37) in the 1990s. Three years ago, the central part also broke up. An international team of researchers used data collected from six (38) near the former ice shelf to show the shelf had been (39) for at least (40) years or since the last ice age. The (41) therefore goes beyond what would be expected naturally at the time. Rather, the (42) is likely the result of (43) due to melting from underneath, as well as short-term (44) from global climate change, the researchers suggest. Then in five years, the shelf shrunk by (45) square kilometers, say scientists who found the break up caused changes in (46) in the area. 'As the ice shelves are disintegrating, the (47) that are feeding them from the land are (48) ,' said Robert Gilbert, a (49) at Queen's University in Kingston, Ont. Glaciers are no longer being held back from the ice shelf, and are pushing (50) into the sea, said Gilbert, one of the co-authors of the study in (51) of the Journal Nature. As the glaciers melt, global sea levels could change more than (52) , he said. Flooding could result in (53) . Scientists are now watching to see if the (54) of the Larsen ice shelf, the coldest part of (55) , is going to break up. (36)