吸收过程为什么常常采用逆流操作？

阅读短文,根据其内容回答问题。

     It's Saturday morning and Tony's sitting at the kitchen table, staring(凝视)into space and playing with

a piece of bread. He's not even hungry. Is he ill? No,  but he does have a problem. He has nothing to do

and there's a simple reason: the Internet is down and Tony has nothing to do.

     When he woke up this morning,  Tony was  feeling great.  He jumped  out of bed full of plans for the

weekend ahead. It would be a weekend like any other-a great weekend. But  that was before he turned

on his computer and was unable to go online. No Internet changed everything.

     Just as Tony is wondering how he can possibly have a normal(平常的)weekend without the Internet,

his mum walks into the kitchen. "Is everything OK?" she  asks. "No, mum, everything is definitely(的确)

not OK," her sad son replies. "I can't go online  and  I  have homework to finish." His mum laughs, "The

word program is still working, so what's the problem?"

     What's the problem? Tony can't believe his  own  mother  is  unable  to  see how serious the problem

really is. To start with, he still needs to do research for his homework. He knows his mum will tell him to

go to the library but he hates the library.  It's  so  dark  and  uncomfortable. And forget homework-what

about the rest of his weekend! Every weekend,  he goes  online to email friends. Then he reads the news

to catch up on what's happening in the world. He plays a few online games and finishes the weekend off

with an online chess game  with  his  cousin  Helen. The  wonderful  weekend-online!  Now it's Saturday

morning and he's not going to have access to(进入)the Internet for two whole days. He needs help.

1．Is Tony busy with the Internet every weekend?

__________________________________________________________________

2．What does he usually do every weekend?

__________________________________________________________________

3．Why did Tony stare and play with a piece of bread?

__________________________________________________________________

4．What might his mother advise him to do?

__________________________________________________________________

5．What do you think of spending a whole weekend online? Why?

__________________________________________________________________

ATM局域网仿真系统中，连接在ATM网络中的主机与网桥可以从逻辑上划分为若干个独立的区域，每个区域称为一个 【14】 。

开展电子商务的目标包括预期效益和（）。

A、实际效益

B、预期净利润

C、实际净利润

D、预期成本

用户可通过（）渠道办理开通国际漫游业务。

A.欢go网站

B.Wap厅

C.短信厅

D.自有营业厅

E.10000号

民用航空器客，货盘舱装载前的清舱工作由（）负责.

A.安检人员

B.机务人员

C.航空器经营人

D.公安人员