* Simple: The volunteer's altruism motivated her to spend her weekends helping at the homeless shelter.
* Emphasis on motivation: Driven by pure altruism, the doctor offered free medical care to the impoverished community.
* Comparison: While some people act out of self-interest, others are guided by altruism.
* Figurative: The company's altruism was questionable; their donation was more a marketing ploy than genuine charity.
* Questioning: Is true altruism possible, or is there always an underlying self-interest?