下列常量中格式正确的是( )。
A．$1.23E4
B．"计算机"等级考试”
C．.False.
D．^2003/01/13
参考答案：D
解析： 货币型常量用来表示货币值，它没有科学记数方法，书写时要在数值前加一个“$”。字符常量也称为字符串，其表示方法是用半角单引号、双引号或方括号把字符串起来(注意符号的匹配)，如果某种定界符本身也是字符串内容，则需要用另一种定界符为该字符串定界。逻辑型数据只有真和假两个值。逻辑真的常量表示形式有：“.t.”，“.T.”，“.y.”和“.Y.”，逻辑假的常量表示形式有“.f.”，“.F.”，“.n.”和“.N.”。
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| It was black in the evening. Jason, a 12-year-old boy didn't want to go outside. But his mother, Branda, was worried about his father and 1 he go. That evening the man had to 2 his car, a Buick outside their house in the driveway. 3 enough, the wife hadn't heard a single 4 for at least one hour. "Go and find him," she told Jason. The kid stepped outside in the darkness and called into the shadows "Dad?" "Jason?" 5 was his father, but his voice sounded 6 . He spoke slowly, in a strange way. That evening, when the man had to get 7 the car to fix it, he used a forklift to lift the car. 8 , the man didn't place the blocks in front of the car' s front tires to keep it from 9 forward off the forks, which was exactly 10 it did afterwards. Little Jason saw his dad's feet 11 out from beneath the car. 12 to take a full breath, Old Jason sank into a sleepy, half-alive 13 . "Calm down. It will be OK." The boy 14 his mother. Now he couldn't afford to be scared. He climbed on and started up, the Buick started to come off the ground and 15 in the air. Minutes later, 911 policemen arrived. Old Jason 16 beneath the car, still breathing. It wasn't 17 his dad was loaded into an ambulance that the little boy 18 and sobbed. Little Jason says one happy change has come out of the 19 : he gets to spend more time with his dad. Old Jason, who hasn't touched a car 20 the Buick fell on him often spends evenings with his son playing. | ||||
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