终端用户和LNS建立PPP连接后，主要协议栈为IPheader、UDPheader和_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题单项选择题

终端用户和LNS建立PPP连接后，主要协议栈为IPheader、UDPheader和L2TPheader。L2TPheader大致（）bytes？

A.20

B.8

C.12

D.10

答案

参考答案：C

完形填空

Tracy Wong is a well-known Chinese-American writer. But her writing   41 was something she picked up by herself. After her first   42  , teaching disabled children, she became a part-time writer for IBM.   43 , writing stories was simply a   44 interest. Tracy sent three of her stories to a publisher(出版商).     45 , they immediately suggested that she put them together to make a single one long   46 and paid Tracy a $50,000 in advance. “A pretty money,” said the publisher, “for   47 writer.”
  48 Tracy’s characters (人物) are interesting, her stories sometimes   49  readers uneasy: those about the supernatural. “My mother believed I could   50  the afterlife world,” she told a close friend. “She used to have me speak with my grandmother, who died many years ago.”
“Can I? I don’t think I can,” Tracy said with a laugh. “But I do have   51 when things come to me  52 .” Once, she was wondering how to complete a    53  set in ancient (古代的) China.   54 the doorbell rang. It was a FedEx delivery man, with a copy of a book on Chinese 55 . It came without her having    56 it.
Though she has published 10 books, Tracy has remained   57  by her fame. She lives in the same   58  she lived 27 years ago — although in a more comfortable home. There’s more room for   59 in her life----and it wasn’t just   60 .

A．Even though

C．Just because

D．Except that

B．connect with

A．for no reason

B．from a distance

C．by accident

A．description

A．Surprisingly

D．Fortunately

判断题

供电企业收取的电，费保证金，一律不缴纳增值税。( )