我从别人那里考了一份stata14，我自己想下载一些命令，却提示下载失败，请问怎样才能下载下来命令啊. ssc install psmatch2,replace
connection timed out -- see help r(2) for troubleshootinghttp://fmwww.bc.edu/repec/bocode/p/ either
  1)  is not a valid URL, or
  2)  could not be contacted, or
  3)  is not a Stata download site (has no stata.toc file).
r(2);