normalit常态, 标准normaladj.正常的；正规的；精神健全的n.常态；标准normalizableadj.可规范化的Normal voice正常音normal class普通班normal setup正常配置normal sound声弘normal force法向力,正交力normal years常年normal steel正常结构钢normal socks男短袜normal group正常基群

1. The condition of the normal eye when parallel rays are focused exactly on the retina and vision is perfect.
   屈光正常当平行光线恰好聚焦于视网膜并形成清晰视觉时正常眼睛的状态