They also help reduce load on busy primary servers, for example ftp. Gnu. Org, and they provide an alternative should one server not be reachable.是什么意思_They also help reduce load on busy primary servers, for example ftp. Gnu. Org, and they provide an alternative should one server not be reachable.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句