【正确答案】 B

【答案解析】[精解] 题干的意思是我们能够预测未来多久的天气。A的意思一天，B的意思七天或者更长，C的意思是五天。文中的细节“Before satellites were invented，the scientists could forecast the weather for about 24 or 48 hours，Now they can make good forecasts for three or five days．Soon，perhaps，they may be able to forecast the weather for a week or more ahead(提前)．”，即在卫星发明以前．气象学家能够预测24到48小时的天气，现在能够预报三五天，也许很快他们能够预报一周或者更长时间的天气状况。故正确答案为B。