朝向

Specifically, a halfmoon betta must have a caudal where both ends are exactly180 degrees apart or more, spreading towards the front.

具体来说，半月斗鱼一定要具备开展方，180°上的尾鳍。

Methods The optometer is composed of singlechip, handle and LCD.The eyesight is examined by selecting exposure of random sample eye-chart mark E within direction keys on the handle.

采用微计算机控制视力检测仪，其由单片机、手柄和液晶显示屏构成，手柄具有上下左右方等功能键，根据手柄上的按键选取随机出现视标"E"的正来检测视力。