知识knowledge可数吗

　　A measure of technical knowledge is desirable in this job.

　　做这项工作最好多懂一些技术知识。

　　He has a wide knowledge of painting and music.

　　他在绘画和音乐方面知识渊博。

　　There is a lack of knowledge about the tax system.

　　大家对税制缺乏了解。

　　For years we had little knowledge of what life was like inside China.

　　以往很多年我们对于中国国内的生活情况所知甚少。

　　He never made a will, to the best of my knowledge.

　　据我所知，他从未立过遗嘱。