题目

阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。Yuan Longping, one of China’s most famous scientists, grows 【1】 is called super hybrid rice. In 1953, Yuan Longping 【2】 ( graduate) from college. As 【3】 young man, he saw the great need for increasing the rice output. Since then he has devoted 【4】 (he) to growing more rice without expanding the area of the fields. In 1973, he became the first 【5】 (agriculture) pioneer in the world to grow rice that has a high output. This special strain of rice makes it possible to produce 20% mo如图1，在等边△ABC中，AD⊥BC于点D，一个直径与AD相等的圆与BC相切于点E、与AB相切于点F，连接EF．（1）判断EF与AC的位置关系（不必说明理由）；（2）如图2，过E作BC的垂线，交圆于G，连接AG，判断四边形ADEG的形状，并说明理由；（3）求证：AC与GE的交点O为此圆的圆心．