1She helped at the charity event voluntarily, without expecting any recognition or reward.
2The company reduced its carbon footprint voluntarily, ahead of the government's new environmental regulations.
3The researchers relied on participants who voluntarily provided their personal data for the study.
4After the natural disaster, many people donated money voluntarily to support the relief efforts.
5The artist created the mural voluntarily, as a gift to the community, without any payment or commission.