voluntary participation的用法和樣例：
例句
- But it is voluntary, leading some critics to say banks taking part are stigmatized.
但這是銀行自愿參與的，一些批評人士對此表示，參與計劃的銀行會(huì )因此蒙羞。 - But a former senior official in Luochuan's health bureau says participation has not been as voluntary as officials make it out to be.
但是，洛川縣衛生局的一位高層官員透露，自愿參與投保的人數比政府公布的要少得多。
