需进行治疗药物监测的药物是() A.庆大霉素 B.普鲁卡因胺 C.地高辛

28、已知数列{a_n}、{b_n}满足：a₁=1，a₂=a（a为实数），且b_n=a_n．a_n+1，其中n=1，2，3，…

（1）求证：“若数列{a_n}是等比数列，则数列{b_n}也是等比数列”是真命题；

（2）写出（1）中命题的逆命题；判断它是真命题还是假命题，并说明理由．

下列有关生物圈稳态的叙述中，不正确的是（　　）

A．太阳能是生物圈存在的能量基础

B．人类的活动对生物圈稳态构成了严重的威胁

C．生物圈稳态与生物多样性的关系不大

D．二氧化碳含量的增加将破坏生物圈稳态

下列税法的构成要素中，( )是区别不同类型税种的主要标志。

A．征税对象

B．税目

C．计税依据

D．纳税环节

阅读理解。

     If you and your friends wish to share a secret, you can write it in code (编码), and no one else will be

able to read it.

     Codes are one way of writing in secret. Ciphers (暗码) are another. In a code each word is written as a

secret code word or code number. In a cipher each letter is changed. Codes and ciphers have played an

important role in the history of the world. Julius Caesar, the Roman ruler who defeated almost all the countries

in Europe about 2, 000 years ago, used a cipher when he sent secret messages to his troops. During the

American Revolution, George Washington's spies used a kind of code to send him information about the enemy

before his military (军事的) action. In World War Ⅱ, the Americans "broke", or figured out, Japan's most

important navy codes and got enough information to destroy a powerful Japanese fleet( 舰队).

     Storekeepers use codes to mark their goods. The codes show how much was paid for the goods or when

 they were added to the stock (商品). Businessmen use codes to hide plans from their business enemies.

Sometimes personal letters or diaries are written in code. Many people enjoy figuring out codes and ciphers

simply as a hobby.

     In the 16th century, codes and ciphers were very popular among scientists. They wrote messages to each

other in code so that no one else would learn their secrets. Geronimo Gardano, an Italian astrologer (星相家),

mathematician, and doctor, invented the trellis cipher. He took two sheets of paper and cut exactly the same

holes in each one. Then he sent one sheet, which he called a trellis, to a friend and kept the other for himself.

Whenever he wanted to write a message, he put his trellis over a clean sheet of paper and wrote the secret

message through the holes. Then he removed the trellis and filled the rest of the paper with words that would

make sense. When his friend received it, he put his trellis over the writing and read the secret message.

1. The best title of this passage is _______.

A. Codes and Ciphers

B. Differences between Codes and Ciphers

C. History of Codes and Ciphers

D. Inventors of Codes and Ciphers

2. Which of the following statements is true?

A. Ciphers can be broken or figured out more easily than codes.

B. You could read some words in Geronimo' s letter without his trellis.

C. The first person who ever used a cipher in history was Julius Caesar.

D. Fondness of using codes was the hobby of the scientists in the 16th century.

3. According to Geronimo Cardano, a trellis is _______.

A. a piece of paper with many small holes

B. a secret message with a lot of small holes

C. a letter with unreadable words and sentences

D. a sheet of paper with groups of Arabic figures

4. It is NOT mentioned in the passage that codes and ciphers are used for the purpose of _______.

A. military affairs　　 　　　　　　　　

B. commercial secrets

C. scientific achievements 　　　　　　

D. personal enjoyment

阅读以下说明和数据流图，根据要求回答问题。

[说明]

某时装邮购提供商拟开发订单处理系统，用于处理客户通过电话、传真、邮件或Web站点所下的订单，其主要功能如下。

1．增加客户记录。将新客户信息添加到客户文件，并分配一个客户号以备后续使用。

2．查询商品信息。接收客户提交商品信息请求，从商品文件中查询商品的价格和可订购数量等商品信息，返回给客户。

3．增加订单记录。根据客户的订购请求及该客户记录的相关信息，产生订单并添加到订单文件中。

4．产生配货单。根据订单记录产生配货单，并将配货单发送给仓库进行备货。备好货后，发送备货就绪通知。如果现货不足，则需向供应商订货。

5．准备发货单。从订单文件中获取订单记录，从客户文件中获取客户记录，并产生发货单。

6．发货。当收到仓库发送的备货就绪通知后，根据发货单给客户发货，产生装运单并发送给客户。

7．创建客户账单。根据订单文件中的订单记录和客户文件中的客户记录，产生并发送客户账单，同时更新商品文件中的商品数量和订单文件中的订单状态。

8．产生应收账户。根据客户记录和订单文件中的订单信息，产生并发送给财务部门应收账户报表。

现采用结构化方法对订单处理系统进行分析与设计，获得如图所示的顶层数据流图和0层数据流图。

请给出图中处理(加工)P1和P2的名称及其相应的输入/输出流。

(2)除加工P1和P2的输入/输出流外，图还缺失1条数据流，请给出其起点和终点。

注：名称使用说明中的词汇，起点和终点均使用图中的符号或词汇。