【单选题】下面关于电子邮件系统叙述错误的是_______。
A.
电子邮件的客户需安装电子邮件程序,负责发送和接收邮件。
B.
用户邮件发送时,邮件传输程序必须与远程的邮件服务器建立连接,并按SMTP协议传输邮件。
C.
用户接收邮件时,按照POP3协议向邮件服务器提出请求,通过身份验证后,便可对自己的邮箱进行访问。
D.
邮件服务器负责接收邮件并存入收件人信箱,以及识别用户身份,进行访问控制,不需执行SMTP、POP3协议。
【判断题】After the industrial revolution, experience-based innovation was increasingly replaced by field experimentation and, later, by science-based experiments conducted in scientific laboratories.
【判断题】根据已知点高程及两点间的垂直角和距离确定未知点高程的测量方法叫水准测量法。()
【单选题】Although he knew _______ little about ________ large amount of work done in the field, he succeeded where more well-informed experiments failed.
【判断题】肾小囊为双层壁围成的囊,血管球位于内层与外层之间。
【判断题】肾小囊为双层壁围成的囊,血管球位于内层与外层之间。
【单选题】Although he knew little about the large amount of work done in the field, he succeeded _______ other more well-informed experiments failed.