I will take part in a voluntary labor instead of just for fun.

我将参加志愿劳动，而不是仅仅为了玩。

youdao

But today we went there to take part in voluntary labor.

但是今天，我们去那是参加义务劳动。

youdao

While (we were) there, we joined in voluntary labor on a project.

我们一到那儿，就自愿参加了这项工程。

youdao

While (we were) there, we joined in voluntary labor on a project.

我们一到那儿，就自愿参加了这项工程。

youdao