I have only a limited knowledge of French.

我只懂得一点法语。

I have only a limited knowledge of computers.

我的计算机知识有限。

I have only a limited knowledge of the subject.

我对这门学科的认识有限。

I have only a limited knowledge of the language.

我对这门语言只有有限的了解。

I am not sure whether it is due to my limited knowledge.

不知道是不是我所见有限。