1. 拥护；提倡；主张
    If you advocate a particular action or plan, you recommend it publicly.

    e.g. Mr Williams is a conservative who advocates fewer government controls on business.
           威廉斯先生是个保守派，主张政府应减少对商业的控制。
    e.g. ...the tax policy advocated by the Opposition.
           反对党提倡的税收政策

2. 拥护者；提倡者
    An advocate of a particular action or plan is someone who recommends it publicly.

    e.g. He was a strong advocate of free market policies and a multi-party system.
           他是自由市场政策和多党派制度的坚决拥护者。

3. 辩护律师
    An advocate is a lawyer who speaks in favour of someone or defends them in a court of law.

4. （为某一类人）谋利益者
    An advocate for a particular group is a person who works for the interests of that group.

    e.g. ...advocates for the homeless...
           为无家可归的人谋利益者
    e.g. Animal rights advocates argue that zoos are really animal prisons and very often cruel.
           动物权利保护者指出动物园实际上是动物的牢笼，经常很残酷地对待动物。