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。
参考例句
1. We will aid their struggle against violent repression. 我们将帮助他们反抗残暴的压迫。
2. A good dictionary can aid language learning. 一“部”好词典有助于语言学习。
3. Red cross aid is also on its way to victims of more than a month of bombings. 红十字会也在抵达的路上，为了救助在长达一个多月的轰炸中的受害者。
英英解释
n.
1. a resource
2. the activity of contributing to the fulfillment of a need or furtherance of an effort or purpose
3. a gift of money to support a worthy person or cause
4. the work of providing treatment for or attending to someone or something v.
1. give help or assistance; be of service
2. improve the condition of
