一年三次用英文怎么说

"Once every three years" or "three times a year" is a common Engpsh expression used to describe an occurrence that happens once every three years.

For example:

"I only visit my hometown once every three years."
"The company holds a major conference three times a year."

This expression is a commonly used time phrase in Engpsh, and is widely understood in both spoken and written contexts.