Adequate/enough/sufficient

(1)    enough 和sufficient 在含义上几乎没有差异，指“充分的；足够的”，表示数量完全满足需要或期望。一般enough 比sufficient 使用更普遍。而在用法上，enough 后面既可以加可数名词也可以加不可数名词。如：enough people 足够人数；enough money 足够的金钱。而sufficient 后面一般只能加不可数名词。如：sufficient sunlight, water and oxygen 充足的阳光、水和氧气；sufficient investigation 充分调查。但也可以用于少数可数名词，如：sufficient funds 足够的资金；sufficient foreign exchange reserves 足够的外汇储备。

(2)    adequate 虽然也表示“足够的；充分的”，但是与enough 和sufficient 二词之间有着细微差异。主要体现在以下两点：(i) adequate 的内涵是：合理的、公平的或不苛刻的，在主观上并不一定是让人满足的，有时往往指满足一个最低或客观标准。如：His wages are adequate to support three people. 这句话说的是：他的工资够养活3个人的。即，这些钱养活3个人够得上一般生活水平。但这些钱可能并不能满足他心里的期望。 而，He has enough money to spend. 他有足够的钱让他去花。 即，表示他的钱完全能够满足他的需要。 (ii) adequate 在表示“充分、足够”时包含了“公平、合理、适当”的意思，其并不单单指数量，更倾向于表示质量、标准或要求。如：adequate compensation 适当补偿；adequate remedy at law 法律上的充分救济；adequate manning 充分的船员配备；adequate disclosure 充分披露。因此在指数量上的足够时，一般用enough 或sufficient 。

从如下例句中可以看出三个词之间的细微差别：

Ø  The pay was adequate, but it certainly wasn’t generous.  The rate of pay was barely adequate to raise a family on.

Ø  His answer to the question was adequate but it wasn’t developed sufficiently to gain high marks.

Ø  The Prime Minister gave an inadequate reply to the journalist’s question.

Ø  There were not enough seats for all the guests.  The supply of seats was quite inadequate.

Ø  There was enough food for everyone.  There was a sufficient amount of food.

Ø  There was insufficient evidence to convict him of house-breaking.

（由得法翻译总结和整理）