政府投资改善公共交通服务对社区至关重要。

Government investment in improving ___public-service transportation is crucial for the community.

他在退休后投身于公共服务，帮助贫困地区的孩子们获得教育机会。

After retirement, he devoted himself to ___public service by helping children in poor areas get educational opportunities.

广播电台每天播放几条公益广告，提醒人们节约用水。

The radio station plays several ___public-service messages daily, reminding people to conserve water.