解放战争开始之初，国民党的力量大大超过共产党，为什么只有三年的时间，国民党反动派就败退到了台湾？

    Bob has summer holidays. He is going to visit his grandparents in Shanghai . He wants to give some presents to them . Yesterday he went to shopping with his mother and father. In the shop , he bought a blue shorts and black pants for his grandfather and some good books for his grandmother . Bob was very happy

明朝时期，收集了1892种药物，11096则药方的“医学巨典”是（   ）