英文字典中noun [S] [C or U] 意思是什麼?

[S] = singular 單數, 強調這個字單數
[C] = countable noun 可數名詞
[U] = uncountable noun 不可數名詞

talent [C or U]
His work shows great talent. [U]
He is a man of many talents. [C] ~ in plural


entertainment [C or U]
There isn't much entertainment for young people in this town. [U]
There's a full programme of entertainments every evening. [C] ~ in plural


[C or U] 只應用在 noun 上
字可以 countable 或 uncountable
看怎樣用
countable noun 可以 singular 或 plural
book ~ singular
books ~ plural

通常 uncountable noun 用 singular verb

Chemistry is difficult.
( is ~ singular verb)

Note:
[S] = singular 單數, 不是加 -s 做複數

genesis 是單數
geneses 是複數

2014-09-08 02:28:33 補充：
countable noun 用 many, few
uncountable noun 用 much, little
"some" 和 "a lot of " 可以用在 both 上

a 和 one 通常只可用在單數 countable noun

重要分別出 noun 是 countable 或 uncountable, or both
好字典有列出
advice, baggage, luggage, furniture 是 uncountable noun
a advice, one luggage, two advices, many luggages 是錯

2014-09-08 02:37:58 補充：
~ quantify uncountable noun
a piece of advice, two slices of bread, three bags of rice

paper [U] = 紙
paper [C] = 文件, 文章, 報紙

Subject/Verb agreement
A slice of bread is on the table.
Two slices of bread are on the table.