阅读理解: The recent heat wave that had broke n temperature records across Europe broke different records when it arrived in Greenland. On August 1, the Greenland Ice Sheet experienced its biggest single-day of ice loss in recorded history. About 12.5 billion tons of ice melted and poured into the Atlantic Ocean, satellite data showed. One day earlier, over 10 billion tons of ice melted. Every 1 billion tons of ice los t creates enough water to fill 400,000 Olympic swimming pools, the Danish Meteorological Institute noted late last week. The center offered the comparison to help people try to understand just how much ice melted. One Danish scientist offered a different comparison. Climate expert Martin Stendl said the total ice that melted in Greenland on July 31 and August 1 could cover all of Germany with seven centimeters of water. Greenland saw its most expansive ice melt on record in July 2012. That month, over 90 percent of the Greenland Ice Sheet was at least partly melting, scientists say. By late July 2012, about 250 billion tons of ice had melted and Greenland’s 2019 melt season could end up breaking the record set in 2012. The recent extreme melting in Greenland was caused by the same burst of hot air that hit Europe in late July. Places across Belgium, Germany, Luxembourg, the Netherlands and Britain broke hot temperature records. Heat waves have always happened, notes Mike Sparrow, an expert. But he says extreme heat waves are happening 10 times more often now than they were a century ago. Mike said that such heat waves are weather events tha t can happen naturally. “But,” he said, “Studies have shown that the frequency and intensity ( 强度 ) ... have increased due to global warming.” 28. Wh y does the author mention two comparisons? A. To stress the amount of melting ice. B. To show the size of a swimming pool. C. To inform the outcome of ice loss. D. To tell the bad weather in Greenland. 29. What can we know from the text? A. A recent heat wave broke world temperature record. B. Most ice sheet in Greenland was partly melting in July 2012. C. The Greenland has lost more ice on July 31 than that on August 1. D. The frequent and intensive heat waves are natural weather phenomena. 30. What does the last paragraph mainly tell us? A. The hot temperature records. B. The reason for heat waves. C. The natural weather events in the world. D. The cause of the extreme melting in Greenland. 31. What is the best title for the text? A. Heat Waves Arrived in Europe B. Greenland Saw Huge Ice Melt C. Europe Experienced Its Hottest Summer D. Global Warming Harmed Greenland Most