once every four years

And maybe it's also because they enjoy the national attention the early caucus or primary brings them for a few months once every four years.

与此同时，他们可能也高兴由于政党基层会议和初选他们每隔四年就有几个月的时间成为全国瞩目的地方。

Annie: Yes. The Olympic Games is held once every four years. The opportunity is rare.

安妮: 对了,四年一届的奥运会, 机会多么难得呀.

Once every four years, during the US primaries, the American media discover the heartland.

每隔四年，在美国大选初选的时候，美国媒体会“发现”美国的中部地区。

The Olympic Games take place once every four years.

10奥林匹克运动会每4年举行一次.

A leap year occurs once every four years.

每四年才有一次闰年.

It is held once every four years, and it last for 16 days.

每四年举行一次, 与奥运会相间举行.会期规定为16天.