Syntax:（句法） RewriteCond TestVerb CondPattern [Flags]TestVerb Specifies verb that will be matched against regular expression.URL - returns Request-URI of client request as described in RFC 2068 ; PatternNS R 要重移动头，FORMAT STRING模式应该生成一个空字符串，例如这一规则将从客户请求中重移代理
