阅读下面材料，在空白处填入恰当的内容（不多于3个词）或括号内单词的正确形式。
Born in 1930, Yuan Longping graduated      Southeast Agricultural College in 1953. Since then, finding ways to grow more rice       (be) his life goal. As a young man, he saw the great    for increasing the rice output. At that time, hunger was a         (disturb) problem in many parts of the countryside. Yuan Longping grows       is called super hybrid rice, making        possible to increase rice harvest without       (expand) the area of the field. Yuan Longping has been considered the first agricultural pioneer in the world    (grow) rice that has a high output.    to his research, the UN has more tools in the battle to rid the world      hunger.