Mother: you hardly go home, we only see you once half a year!
妈：你也难得回家，我们半年才看到你一次啊。
When he was a pilot, he once did not come back home for half a year during a mission.
当他是一名飞行员时，他曾在一次任务期间半年不回家。
Almost half use them once a year at most.
有将近一半的人每年最多只乘坐一次列车。
In a few months or half a year, go over the first book once again.
过几个月或半年，把第一本书再复习一遍。
During long term storage, battery should be charged and discharged once every half a year.
经过长时间存放，电池应每三个月进行一次充放电。
During long term storage, battery should be charged and discharged once every half a year.
经过长时间存放，电池应每三个月进行一次充放电。
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