assist

aid, assist, help

这些动词均有“帮助”之意。
aid: 正式用词，指帮助他人脱离危险或战胜困难，着重强者对急需帮助的弱者的帮助。
assist: 强调在提供帮助时，以受助者为主，所给的帮助起第二位或从属的作用。
help: 最普通用词，含义广泛。指一般性的或迫切需要的帮助，侧重积极地为他人提供物质、精神或其他方面的帮助。

名词 assist:

1. the activity of contributing to the fulfillment of a need or furtherance of an effort or purpose
   同义词：aid, assistance, help
2. (sports) the act of enabling another player to make a good play

动词 assist:

1. give help or assistance; be of service
   同义词：help, aid
2. act as an assistant in a subordinate or supportive function
3. work for or be a servant to
   同义词：serve, attend to, wait on, attend

1. He asked us to assist him in carrying through his plan.
   他请求我们帮他完成他的计划。
2. Relating to, assisting, or intended to assist the memory.
   帮助记忆的有关，帮助，或试图帮助记忆的
3. A team of nurses assisted the doctor in performing the operation.
   一组护士协助医生施行手术。

as.sist

v.（动词）
as.sist.ed,as.sist.ing,as.sists
v.tr.（及物动词）
To give help or support to, especially as a subordinate or supplement; aid:
帮助：给…帮助或支持，尤指作为棣属形或补充型；帮助：
例句：
The clerk assisted the judge by looking up related precedents. Her breathing was assisted by a respirator.
这位书记官协助那位法官查阅有关判例。她要靠呼吸器帮助呼吸

v.intr.（不及物动词）
To give aid or support.See Synonyms at help
援助：给予帮助或支持参见 help
To be present, as at a conference.
出席：在场，如出席会议
n.（名词）
An act of giving aid; help.
助人行为；帮助
Sports
【体育运动】
A fielding and throwing of a baseball in such a way that enables a teammate to put out a runner.
助杀，助攻：能使同队伙伴击败另一击球者将垒球掷于地或抛出
A pass of a basketball or an ice hockey puck that enables a teammate to score a goal.
助杀，助攻：在篮球赛或冰球比赛中传球以使同队伙伴进球得分
The action of a soccer player who enables a teammate to score by presenting the ball for a goal.
助杀，助攻：把足球踢给同队伙伴以射门的行为
Official credit that is given for such an act.
给予此类行为的官方荣誉
A mechanical device providing aid.
机械辅助装置：能提供帮助的机械设备

来源：
Middle English assisten
中古英语 assisten
from Old French assister
源自 古法语 assister
from Latin assistere
源自 拉丁语 assistere
ad- [ad-]
ad- [前缀，表.朝，向.]
sistere [to stand] * see st3-
sistere [站立] *参见 st3-

【引伸】
assist.er
n.（名词）