某工程网络计划有三条独立的线路A-D、B-E、C-F，其中B-E为关键线路， TFA

设函数f（x）=lg（x²+ax-a-1），给出下述命题：①f（x）有最小值；②当a=0时，f（x）的值域为R；③若f（x）在区间[2，+∞）上单调递增，则实数a的取值范围是a≥-4．则其中正确的命题的序号是______．

阅读理解

Section One

     The city is an accumulation (积累)of human civilization. Just as the American social philosopher

(哲学家) Lewis Mumford put it, it is a special system which, fine and compact（简洁的）, has been

designed to preserve the fruits of human civilization. Many Western languages have developed their

versions of the term “civilization” from the same Latin (拉丁语的) word “civitas”(meaning “city”), and

it is by no means a coincidence（巧合）. The city has played a significant role in the perfection of

order in human society.

Section Two

     The emblem, showing the image of three people  ? you, me, him/her holding hands together,

symbolizes the big family of mankind. Inspired by the shape of the Chinese character “世”

(meaning the world), the design conveys the organizers' wish to host an Expo which is of global

scale and which displays the various urban cultures of the world.

Section Three

     Created from the inspiration of Chinese character “人”, the design roots deeply in Chinese culture.

It tells the world the eternal core (永恒的核心) and theme of Shanghai World Expo will be always

human. The mascot（吉祥物） “Haibao” will become the messenger for the theme of

World Expo 2010 Shanghai China “Better City, Better Life”.

     The basic structure of the Chinese character “人” in which each stroke(一笔，一划) supports

each other also shows the concept that the beautiful life should depends on mutual-help. If the human

are willing to support one another, the harmony among human, nature, and society will be available.

Such an urban life will be nice.

     Haibao’s confident smile is expressing his sincere greeting from China ? “World Expo 2010

Shanghai China welcomes you!”

1. Section One mainly tells us about ______.

    A. the part cities play in human civilization  

    B. the development of the word “city”

    C. why the Expo is held in Shanghai  

    D. where human civilization originated

2. The underlined word “it” in Section One refers to ______.

    A. the civilization

    B. the philosopher

    C. the word

    D. the city

3. Which correctly matches the sections with the pictures described in the passage?

4. The second paragraph in Section Three explains how the creation is connected with the _____ of 

    the  Chinese word “人”.

    A. story   

    B. meaning

    C. shape   

    D. usage

信号机应在列车运行方向的（）或其所属线路的中心线上空。

下列关于银行债券投资业务的表述，正确的有( )。

A．国债是银行最安全的中长期投资品种

B．国债是银行最主要的中长期投资品种

C．国债是银行最具流动性的中长期投资品种

D．我国的公司债包括企业债和金融债

E．银行可以将金融债作为投资和融资的工具

某一项目如果满足资产定义，必须确认为资产。 ( )