knowledge可数不可数

　　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。

　　She has acquired a good knowledge of English.

　　她英语已经学得很好。

　　Our knowledge of the disease has advanced considerably over recent years.

　　近年来我们对这种疾病的了解深入多了。

　　To my certain knowledge he was somewhere else at the time.

　　我敢肯定他当时在别处。