这位年轻的拳击手在赢得所有比赛后成为了全国冠军。

The young boxer became the national ___champion after winning all his matches.

她一直公开支持环保事业。

She has always ___championed environmental protection.

他一直是环保事业的坚定拥护者。

He has been a strong ___champion of environmental causes.