单选题 It has been estimated that the earth's surface temperature has increased ______one quarter to three fourths of a degree since 1850.
【正确答案】 A
【答案解析】[注释] 应该掌握选择项中四个介词的不同用法，修饰数字的介词一般为“by”，所以A项正确。全句意思为“据估计，从1850年以来，地表温度增加了0.25到0.75度”。