预精馏塔加萃取水对精馏操作起到什么作用？

阅读理解。

     "Tom? Are you in bed yet?" called Mrs White. There was no answer. Mrs White put down her book and

went to her 14-year-old son's room. Tom was sitting in front of a bright computer screen on which a colorful

dragon(龙) jumped and shouted. 

     "Oh, Tom! You're still playing on that computer. You must stop now, it's half past eleven. If you don' t go

to bed soon, you'll be very tired tomorrow," said Mrs White. 

     "But I've nearly beaten the dragon," said Tom. Mrs White could see the excitement (激动) on her son's

face. She sat down beside him. 

     "You are always playing on that computer. You spend more time with this machine than with your family,"

she said with a smile. "What's so special (特别的) about it? Show me what it can do!" 

     Tom was very excited. "I think this is a very good computer, Mum!" he said happily. "There's so much

memory(内存) and it has some wonderful software programmes. This game, Dragonsplayer, is my favourite,

but I sometimes borrow games from Danny and other friends. I don't have to worry about any infected

(被感染的) disks (磁盘) because I have a virus(病毒) detector(监测器) which can go over any disk and

check it for viruses. Let me show you!" Tom began tapping(敲打) keys on the keyboard(键盘). The screen

changed in answer to his orders(命令). 

     "Oh, Tom," laughed Mrs White, "I'm sure it's a wonderful computer, but I' m afraid I don't know what

you're talking about."

阅读短文，判断正(T)误(F)。

( ) 1. When Mrs White was calling Tom, he was lying in bed reading.

( ) 2. This story happened after Tom had slept for some hours in the evening.

( ) 3. Tom was very excited because he had nearly beaten the dragon in the computer.

( ) 4. Tom liked playing computer games very much.

( ) 5. Tom didn' t want to talk about the computer with his mother.

甘特特别出名的原因是他发明了（）。

根据《处方药与非处方药分类管理办法（试行）》，关于药品按处方药与非处方药分类管理的说法，正确的是（）

A.按照药品品种、规格、给药途径及疗效的不同进行分类

B.按照药品类别、规格、适应症、成本效益比的不同进行分类

C.按照药物经济学评价指标中的风险效益比与成本效益比的不同进行分类

D.按照药品品种、包装规格、适应症、剂量及给药途径的不同进行分类

E.按照药品品种、规格、适应症、剂量及给药途径的不同进行分类

关于跨国（地区）公司的叙述正确的是（）

A.工业集聚的产物

B.工业分散的产物

C.目的在于减少运费

D.下属子公司之间不存在联系