从词性用法上比较good只用作形容词，不用作副词，其副词形式用well。well既可用作副词，也可用作形容词。用作形容词时，其用法很有限，只表示“健康的”“恰当的”或“令人满意的”等。
goodwell的区别和用法从相关短语用法上比较
be good at 与 do well in：两者均可表示“擅长”。如：
He is good at languages. 他擅长学语言。
She is good at telling stories. 她擅于讲故事。
They all did very well in the examination. 他们这次都考得很不错。
注：表示擅长某一学科时，也可用be good in。如：
He is good at [in] maths. 他擅长数学。
2. as good as 与 as well as：用于本义时，两者均可表示“与……一样好”，但 good 是形容词，而 well 是副词。如：
他说英语说得跟她一样好。
正：He speaks English as well as her.
正：His English is as good as hers.
但是，用于引申义时，两者的意思很不相同：as good as 意为“几乎”“差不多”(=almost)，as well as 意为“而且”。如：
The work is as good as finished. 工作差不多干完了。
He as good as said I’m a liar. 他无异于说我撒谎。
She’s clever as well as beautiful. 她不但漂亮，而且聪明。
As well as breaking his leg, he hurt his arm. 他不但摔断了腿, 而且还伤了胳膊。
