英语中knowledge是一个名词，意思是知识，它常常用作不可数名词。例如

俗话说，知识就是力量， As the old saying goes，knowledge is power。

但knowledge常使用固定搭配have a good knowledge of。意思是具有……知识，精通掌握。可以替换为have a good command of。

例如

She is a girl who has a good knowledge of spoken English.