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. to back the cause up with their lives 用他们的生命支持这一事业
2. Do you have back or neck pain? 你有背痛或颈部酸痛问题吗？
3. Back to hostel yet? To eat yet? 回到宿舍了没有？吃饭了没有？
英英解释
n.
1. the posterior part of a human (or animal) body from the neck to the end of the spine
2. the side that goes last or is not normally seen
3. the part of something that is furthest from the normal viewer
4. (football) a person who plays in the backfield
5. the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
6. the protective covering on the front, back, and spine of a book
7. the part of a garment that covers the back of your body
8. a support that you can lean against while sitting
9. the position of a player on a football team who is stationed behind the line of scrimmage v.
1. be behind; approve of
2. travel backward
3. give support or one's approval to
4. cause to travel backward
5. support financial backing for
6. be in back of
7. place a bet on
8. shift to a counterclockwise direction
9. establish as valid or genuine
10. strengthen by providing with a back or backing adj.
1. related to or located at the back
2. located at or near the back of an animal
3. of an earlier date adv.
1. in or to or toward a former location
2. at or to or toward the back or rear
3. in or to or toward an original condition
4. in or to or toward a past time
5. in answer
6. in repayment or retaliation
