第23题: [单项选择]先天性白内障发病率最高的类型是() A. 囊膜性白内障 B. 缝合性白内障 C. 绕核性白内障 D. 先天性全白内障 E. 极性白内障 参考答案:C 答案解析:备选答案是各类重要的先天性白内障的类型。考生需掌握各类常见先天性白内障的发病率。绕核性白内障的发病率占先天性白内障的50%;全白内障的发病率次之,为20%;其余类型发病率更少。
A. it was very durable B. the tools and weapons were made of stone C. there was little vegetation D. the people lived in caves 参考答案:B 答案解析:[听力原文]11-13 The Stone Age was a period of history which began in approximately 2 million B.C.