once a year
once a year(一年一次),确定用 how often提问;
annually
... Annually(一年一次) Semi-annually(半年一次) Quarterly(每季一次) ...
Once in a year
... Once half a year 半年一次 Once in a year 一年一次 Least Once A Year 最少举行一次会议 ...
yearly
一年一次(yearly), 此释义来源于网络辞典。
annual ; yearly ; on annual basis
Almost once a year ; Almost a year
Yearly Visit