要查看PDF文件，您需要安装Adobe Acrobat Reader。如果你尚未安装，免费下载的 http://www.adobe.com/products/acrobat/readstep.html

To view pdf files, you will need Adobe Acrobat Reader. If you do not have it installed, download it for FREE at http://www.adobe.com/products/acrobat/readstep.html