阅读理解。阅读下列短文, 从给的四个选项 (a、b、c和d) 中, 选出最佳选项。
the earth is getting warmer. over the past 100 years earth’s temperature rose by about 1°f. scientists predict that earth will continue to warm by about 2—6°fover the next 100 years. that may not sound like much, but think about this: during the last ice age, earth was only 9°f cooler than it is today, and large sheets of ice called glaciers(冰河) covered large parts of north america! the warming of earth’s climate is
