这家律师事务所为困难家庭提供无偿法律咨询。

Zhè jiā lǜshī shìwùsuǒ wèi kùnnan jiātíng tígōng wúcháng fǎlǜ zīxún.

This law firm provides free legal consultation for families in difficulty.

他把自己收藏的书无偿捐给了学校图书馆。

Tā bǎ zìjǐ shōucáng de shū wúcháng juān gěi le xuéxiào túshūguǎn.

He donated his book collection to the school library free of charge.

国家鼓励公民积极参与无偿献血活动。

Guójiā gǔlì gōngmín jījí cānyù wúcháng xiànxuè huódòng.

The state encourages citizens to actively participate in voluntary blood donation.