复数形式的knowledges用得对吗

The Internet has become an important part of teenage life. Most of them use the Internet to get lots of knowledges and information, and to relax in their spare time.

不是说 knowledge 是不可数名词吗？这里为何用复数？

显然是中国人写的句子，原句有错，正如你所觉得的一样，knowledge 是不可数名词，不可以用复数。应改用单数：

The Internet has become an important part of teenage life. Most of them use the Internet to get lots of knowledge and information, and to relax in their spare time.

句意：网络已经成为青少年生活的要紧组成部分。他们中的大部分人借助网络获得很多的常识和信息，并在空闲时间用它来放松自己。