Accurate Timer These days time is everything. Between meetings and appointments, deadlines and conference calls, my schedule

admin2012-09-10  35

问题                           Accurate Timer
    These days time is everything. Between meetings and appointments, deadlines and conference calls, my schedule requires that I know the time down to the minute. Even on weekends, I have a football team to coach, shows to tape and planes to catch. If I’m late, I’m sunk. The problem is that it’s hard if my clocks aren’t correct. Even the digital clocks can display time inaccurately. Dead batteries, time changes, any of these can cause a clock to be inaccurate. Now there is no need to worry, because advanced radio technology has produced a clock which gets the time directly from the U.S. Atomic Clock in Fort Collins, Colorado, the standard for time-keeping all over the world. The Atomic Clock by Acorn is the most accurate, reliable and convenient timepiece you can have.
    Every morning at 1:00 a. m, this "smart" clock in Colorado automatically resets itself to the exact hour, minute and second. The U. S. Atomic Clock is accurate to ten billionths of a second per day. This means that the clock deviates less than one second over a one million-year period. The Atomic Clock even adjusts automatically for daylight saving time, so you don’t have to remember to "spring forward" or "fall back". The desktop clock model is the only atomic Clock that will not lose time with low power or when you change its batteries.
    The most accurate clock in the world is of no use if it is difficult to operate. The Acorn Atomic Clock is engineered in Germany using the latest scientific technology. It comes in two styles, the wall clock and the desktop model. Both are designed to be functional and easy to use. The desk clock’s display features the exact time (in hours, minutes and seconds), month and date, or you can choose to display any two U. S. or world time zones. It weighs only eight ounces, and is the perfect travel clock It also has dual alarms, perfect for couples. Both the desktop and the wall models have an internal antenna for good reception without unattractive wires.
The U.S. Atomic Clock is so accurate that______.

选项 A、it gains only a second in a million years
B、its deviation is within a second in a million years
C、it loses only a second in a million years
D、its deviation can never be detected

答案B

解析 本题考查考生对细节的把握。考的是艾克瑞恩制作的原子钟计时的精确程度。答案的线索在第二段第二、三句话:The U. S. Atomic Clock is accurate to ten billionths of a second per day. This means that the clock deviates less than one second over a one-million-year period. 所以,正确答案是B。
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