A. when they have received satellite pictures B. during they study satellite pictures C. after they have compared new satellite pictures with earlier ones 参考答案:C 答案解析:[精解] 题干的意思是气象学家何时预报天气。A的意思是当他们接收到卫星图片时,B的意思是在他们研究卫星图片的过程中,C的意思是在他们和早期的卫星图片比较后。文中的相关细节为"When they rec