you know it is very important to understand these things，so I copy many links and screenshot as the following
https://technet.microsoft.com/en-us/library/cc749113(v=ws.10).aspx
https://technet.microsoft.com/en-us/library/cc766376(v=ws.10).aspx
SCVMM-04 Understanding Answer Files
原文：http://10500561.blog.51cto.com/10490561/1770676