knowledge是否可數及用法

例句：

1、A measure of technical knowledge is desirable in this job.

做這項工作最好多懂一些技術知識。

2、 He has a wide knowledge of painting and music.

他在繪畫和音樂方面知識淵博。

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

以往很多年我們對於中國國內的生活情況所知甚少。

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

據我所知，他從未立過遺囑。