CURLOPT_PORT：一个可选的用来指定连接端口的量；

CURLOPT_PROXYAUTH：The HTTP authentication method(s) to use for the proxy connection. Use the same bitmasks as described in CURLOPT_HTTPAUTH. For proxy authentication, only CURLAUTH_BASIC and CURLAUTH_NTLM are currently supported.

CURLOPT_PROXYPORT：The port number of the proxy to connect to. This port number can also be set in CURLOPT_PROXY.

CURLOPT_PROXYTYPE：Either CURLPROXY_HTTP (default) or CURLPROXY_SOCKS5.

CURLOPT_RESUME_FROM：在恢复传输时传递一个字节偏移量(用来断点续传)

CURLOPT_SSL_VERIFYHOST：

1 to check the existence of a common name in the SSL peer certificate.

2 to check the existence of a common name and also verify that it matches the hostname provided.

CURLOPT_SSLVERSION：The SSL version (2 or 3) to use. By default PHP will try to determine this itself, although in some cases this must be set manually.

CURLOPT_TIMECONDITION：如果在CURLOPT_TIMEVALUE指定的某个时间以后被编辑过，则使用CURL_TIMECOND_IFMODSINCE返回页面，如果没有被修改过，并且CURLOPT_HEADER为true，则返回一个"304 Not Modified"的header，CURLOPT_HEADER为false，则使用CURL_TIMECOND_ISUNMODSINCE，默认值为CURL_TIMECOND_IFMODSINCE

CURLOPT_TIMEOUT：设置curl允许执行的最长秒数

CURLOPT_TIMEVALUE：设置一个CURLOPT_TIMECONDITION使用的时间戳，在默认状态下使用的是CURL_TIMECOND_IFMODSINCE

CURLOPT_CAINFO：The name of a file holding one or more certificates to verify the peer with. This only makes sense when used in combination with CURLOPT_SSL_VERIFYPEER.

CURLOPT_CAPATH：A directory that holds multiple CA certificates. Use this option alongside CURLOPT_SSL_VERIFYPEER.

CURLOPT_COOKIE：设定HTTP请求中“Set-Cookie:”部分的内容。

CURLOPT_COOKIEFILE：包含cookie信息的文件名称，这个cookie文件可以是Netscape格式或者HTTP风格的header信息。

CURLOPT_COOKIEJAR：连接关闭以后，存放cookie信息的文件名称