back 通常指对论点、行动、事业等的强有力支持。
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。
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。
sustain 侧重指连续不断的支持。
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。
参考例句
1. The speech made by the president was supported widely by the public. 总统的演说获得广大民众的拥护。
2. Again, this is a support system issue. 这又是一个证明制度的问题。
3. Think of their cry of undying support ! 想想他们无休止的喝彩支持！
英英解释
n.
1. the activity of providing for or maintaining by supplying with money or necessities
2. aiding the cause or policy or interests of
3. something providing immaterial assistance to a person or cause or interest
4. a military operation (often involving new supplies of men and materiel) to strengthen a military for
5. documentary validation
6. the financial means whereby one lives
7. supporting structure that holds up or provides a foundation
8. the act of bearing the weight of or strengthening
9. a subordinate musical part; provides background for more important parts
10. any device that bears the weight of another thing
11. financial resources provided to make some project possible v.
1. give moral or psychological support, aid, or courage to
2. support materially or financially
3. be behind; approve of
4. be the physical support of; carry the weight of
5. establish or strengthen as with new evidence or facts
6. adopt as a belief
7. support with evidence or authority or make more certain or confirm
8. argue or speak in defense of
9. play a subordinate role to (another performer)
10. be a regular customer or client of
11. put up with something or somebody unpleasant
