do a good deed

基本解释

It could have been just another man doing a good deed.
他可能只是一个正在做好事的人。
Of course, while doing a good deed we should also use our head.
当然，在做好事的时候我们要用用脑。
Would you qualify volunteering your time to a worthy cause, giving food to a homeless person, or doing a good deed as “getting things done”?
你会严格规定你自愿服务一件有意义的事情上面的时间，限制给一个无家可归的人食物或是做一件好事列在”必须要做的事情清单上"吗？

In 2009, William Marotta thought he was doing a good deed by donating his sperm to a same-sex couple looking to conceive.
FORBES: Why This Sperm Donor Is Being Ordered To Pay Child Support
Take the case of David, a financial professional from New York who's doing a good deed and had no idea he was opening himself up to swindlers.
NPR: Identification Theft: Protecting Your Personal Data
"We're doing a good deed for our customers, " he says.
FORBES: Good Will Hunting