自愿

zhè shì zì jué zì yuàn de xíng wéi

这是自觉自愿的行为。

This is voluntarily behavior.

zhè ge bǐ sài zì yuàn cān jiā

这个比赛自愿参加。

This competition is voluntary.

tā zì yuàn dào xiāng cūn gōng zuò

她自愿到乡村工作。

She volunteers to work in the countryside.

wán quán chū yú zì yuàn

完全出于自愿

completely on a voluntary basis

zì yuàn xiào láo

自愿效劳

volunteer one's services

zì yuàn fú yì

自愿服役

volunteer for military service

zì yuàn bào míng

自愿报名

enter one's name voluntarily