他捐赠了全部积蓄帮助灾区重建，真是个无私奉献的人。

He donated all his savings to help rebuild the disaster area, proving he's a true ___altruist.

这位医生放弃高薪工作去贫困地区行医，是真正的利他主义者。

The doctor who gave up a high-paying job to work in poor areas is a true ___altruist.