back、uphold、support、sustain与advocate这些动词均有“支持、支援、拥护”之意。

back : 通常指对论点、行动、事业等的强有力支持。

Doctors have backed plans to raise the tax on cigarettes.

医生们对提高烟草税计划给予了支持。

a United Nations-backed peace plan

得到联合国支持的和平计划

uphold : 既可指积极努力对陷入困境者的支持，也可指给某人在行动、道义或信仰上的支持。

As a police officer you are expected to uphold the law whether you agree with it or not.

作为警察，不管你赞成与否都应该维护法律。

Judge Davis upheld the county court's decision.

戴维斯法官维持了郡法院的判决。

support : 含义广泛，多指在道义上或物质上支持某人，也可指对某项事业的支持。

My father supported the LabourDemocratic Party all his life.

我父亲毕生都拥护工党／民主党。

The majority of people in the town strongly support the plans to build a new school.

镇上的大部分人都强烈支持修建新学校的计划。

I think it's important to support local businesses by buying locally.

我认为购买本地商品来支持本地企业这一点很重要。

sustain : 侧重指连续不断的支持或情感上的支持。

The cash dividends they get from the cash crop would sustain them during the lean season.

从经济作物中获得的收益能帮助他们度过不景气的时期。

She was sustained by the strength of her religious faith.

宗教信仰的力量支撑着她。

The love of my family and friends sustained me through my ordeal.

家人和朋友的爱支撑着我渡过了难关。

advocate : 多指通过写文章或发表演说等来支持或拥护，往往暗示提倡某事或为某事辩护。

She advocates taking a more long-term view.

她主张把目光放得更长远一些。

He advocates the return of capital punishment.

他主张恢复死刑。

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。