He's supplying blood for his sister-in-law, who suffers from kidney complications.

VOA: standard.2010.06.04

For example, if your son got in a fight with his sister and you're very concerned about him,

例如，如果你的儿子跟他的妹妹打了起来，你对他很是担心，

I need 课堂 - SpeakingMax英语口语达人

He said he knew the organization was great because his sister had volunteered for it.

VOA: special.2009.04.03

But Montclin had an idea for securing his sister's freedom.

VOA: special.2009.06.27