纸币的发行量必须以流通中所需要的货币量为限度。

在代数式x²+ax+b中，当x=2时，它的值为3；当x=-2时，它的值为19，则a=______，b=______．

二、完形填空（共20小题；每小题1. 5分，满分30分）

Years ago, if a teenager had some problems in her life, she might go home and write in her diary. Now, a teenager with   16   problems might go onto the Internet and write about his problems in a blog. In many ways a diary and a blog are very   17  . So, what makes blogging different from writing in   18   diary?

The biggest difference is that blogging is much more   19   than a diary. Usually, a teenager treats his diary like a book full of   20   that she does not want to   21 

It’s interesting that someone who writes in a blog   22   a diary will probably write nearly the same information.

I have a little sister, and sometimes I go online to read her   23   . She writes about things like waking up early for swimming practice and not studying enough for her chemistry test.  24  I was her age, I wrote about the same things, but   25   in my diary. Then, after I had finished writing, I would hide my diary in a secret place because I was   26   that my sister might read it!

The biggest   27   with blogging is that anyone can read what you write. If I was angry with a friend during high school and wrote something   28   about her in my diary, she would never know!   29, if my sister ever wrote something bad about a friend, that friend   30  read her blog and get a “cry”.

There are also   31   to blogging, of course. If I felt sad one day and wrote in my diary: “Nobody cares about me.”   32   would know about it. However, if my sister wrote the same sentence in her blog, her best friends would   33   respond（回应）and tell her how much they  _34   her. Blogs help people   35   in contact with their friends and know what the people around them are doing.

16. A. the same      B. troublesome       C. difficult      D. daily

17. A. familiar          B. special              C. similar            D. different

18. A. a personal    B. an ordinary     C. a common   D. a traditional

19. A. attractive     B. public         C. convenient   D. quick

20. A. thoughts      B. puzzles          C. mysteries     D. secrets

21. A. tell         B. share          C. publish        D. solve

22. A. instead of     B. as well as      C. in favor of   D. in spite of

23. A. blog        B. diary          C. report       D. web

24. A. Although     B. Since         C. When       D. Because

25. A. only        B. already          C. still          D. never

26. A. angry      B. concerned      C. glad         D. worried

27. A. problem          B. doubt         C. trouble            D. mistake

28. A. boring     B. wrong         C. unpleasant   D. funny

29. A. Beside     B. However       C. Therefore    D. Then

30. A,. should     B. will           C. must        D. might

31. A. reasons     B. disadvantages     C. shortcomings D. advantages

32. A. everyone      B. no one              C. anyone        D. someone

33. A. happily     B. especially      C. quickly       D. immediately

34. A. like         B. miss           C. need        D. help

35. A. lose         B. stay           C. get           D. find

在道路上跟车行驶时，跟车距离不是主要的，只须保持与前车相等的速度，即可防止发生追尾事故。

小雨同学用湿手拿一个装满了酒的大瓶子，她感到瓶子往下滑，这是因为手上有了水，摩擦力________。于是她更加用力地握紧了瓶子，这样做的目的是通过________来增大摩擦；单杠运动员上杠前，手上先涂镁粉，这样做的目的是为了________摩擦。