knowledge是可数名词吗？knowledge和knowledges有什么区别？

knowledge常用的是不成数,但也可数。做不成数名词，泛指常识 ；做不成数名词,只做为单数,理解为把握,晓得,一般用法为a + 描述词 +knowledge（暗示一种特定的常识）。

释义：n. 常识，学问；晓得，熟悉；学科n. (Knowledge)人名；(南非)诺利奇

一般都是接of have a knowledge of 懂一点；晓得;领略；对…熟悉 I have a thorough knowledge of the English language.我熟知英语。 I have a knowledge of astronomy.我懂一点天文学。 He has a good knowledge of London.他对伦敦很熟悉。 he has a superior knowledge of magic.他有头角峥嵘的魔术常识。 I have only a sketchy knowledge of geography.我对天文只是一知半解。