当你手上读到一篇PDF格式文件时，想摘取其中的一些感兴趣的资料，却没有修改权限时，可以用这个软件去除限制，但修改还要用其它PDF编辑软件。软件很小，可以满足你的需要。-When you read a PDF format file on hand when you want to extract some of the interesting information, but not modify the permissions, you can use this software to remove the restriction, but changes also with other PDF editing software. The software is very small, to meet your needs.