A black ring was engraved on the end of the strip, so that the gunner saw two graticule rings, one fixed, the other on the celluloid.是什么意思_A black ring was engraved on the end of the strip, so that the gunner saw two graticule rings, one fixed, the other on the celluloid.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句