Originally introduced by Netscape Communications, (21) are a general mechanism which HTTP Server side applications, such as CGI (22) , can use to both store and retrieve information on the HTTP (23) side of the connection. Basically, Cookies can be used to compensate for the (24) nature of HTTR The addition of a simple, persistent, client-side state significantly extends the capabilities of WWW-based (25) .

A．fixed

B．flexible

C．stable

D．stateless

对于电动电势的描述，下列说法正确的是（）。

A.电势易随电解质性质及浓度而变

B.电势的绝对值一般大于热力学电势

C.憎液溶胶的电势等于零的状态，称为等电态

D.当胶体粒子与液相发生相对移动时，滑动面与溶液本体之间的电势差，称为电势