a boon for sb or a boon to sb对某人大有裨益的东西
The bus service is a great boon to old people.公交服务给老人带来了极大的方便。
It is for this reason that television proves such a boon to so many people.正是这个原因, 电视才会给这么多人带来如此大的便利。
This battery booster is a boon for photographers.这款电池充电器对摄影师来讲非常有用。