occasionaladj.偶然的;临时的;不时的
occasional irregularity偶然异常
occasional fatal trauma偶然的致命伤
occasional regeneration偶然再生
occasional transmission非经常传输
occasional thunderstorm间中有雷暴
occasional insemination偶然授精
occasional moulding pit通气造型坑
occasional premature beat偶发早搏
occasional parthenogenesis偶发性单性生殖
occasional monograph series不定期出版的专题丛刊