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问题 选择题

无论x取何实数，点P（x,-2x+3）一定不在

A．第一象限；

B．第二象限；

C．第三象限；

D．第四象限．

答案

答案：C

解：①当x是正数时，-2x+3可以是正数，也可以是负数，

∴点P可以在第一象限，也可以在第四象限；

②当x是负数时，-x＞0，

∴-2x+3＞0，

此时点P一定在第二象限，

综上所述，点P一定不再第三象限．

故选C．

单项选择题

下面哪一项不是文件系统的功能( )。

A．文件系统实现对文件的按名存取

B．负责实现数据的逻辑结构到物理结构的转换

C．提高磁盘的读写速度

D．提供对文件的存取方法和对文件的操作
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填空题



In the early 1970’s, Citibank of New York City became one of the first financial institutions to install ATM’s on a large scale. Since then, the (1) of automated teller machines has increased dramatically. At the time, the bank hoped (2) their operating costs by replacing human tellers with machines. Little did they (3) that the cash machines would become so successful. However, as more banks added (4) automated service through ATM’s, the machines mushroomed all over the world.
To use an ATM, all you need is a (5) issued by your bank. Your bank may also (6) through a credit card, such as MasterCard or Visa. To begin a (7) , you need to insert the card into an ATM and punch in a personal identification number on the (8) . The personal ID number may consist of (9) and can prevent anyone from using the card.
The ATM next flashes instructions on its (10) for carrying out transaction. To get cash, for example, you are instructed to (11) that indicate whether the money should be withdrawn from a checking or a savings account and the (12) . This request is then displayed on the screen. After you press a button to (13) that the information is correct, the ATM goes to (14) .
How safe, you may ask, is banking by ATM The (15) is meant to prevent anyone, no matter who you are, from using a cash card (16) . If you enter the wrong ID number for a card, a message on the screen will (17) . If you fail to produce the correct number for three times, most machines will (18) .As another precaution against (19) , the bank generally limits the amount that may be withdrawn by cash card (20) , say, to $ 200.
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