spontaneous ☊ 
自愿 → ☊ 
sẵn lòng tự nguyện 
willingly like: tự nguyện → →
freiwillig ☊ 
tự nguyện ☊ 
自愿的 ☊ zì yuàn de freiwillig ☊ tự nguyện ☊ ☊ Voluntary work was particularly important in view of the fact that women were often forced to give up paid work on marriage. ☊ fact ☊
influence sb to do sth: She was influenced to take up voluntary work by her teacher. ☊ influence ☊
to work for a business/political/voluntary organization ☊ organization ☊
The agency is voluntary and not run for profit. ☊ profit ☊
The charity is run on a purely voluntary basis. ☊ purely ☊
The staff have agreed to a voluntary wage freeze (= a situation in which wages are not increased for a time). ☊ wage ☊