题目内容

用程序计算一个整数的各位数字之和,在下划线处应填写的语句是( )。 SET TALK OFF INPUX“X=”FO X S=0 DO WHILE X!=0 S=S+MOD(X,10) ENDDO S SET TALK ON

A. X=int(X/10)
B. X=int(X%10)
C. X=X-int(X/10)
D. X=X-int(X% 10)

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在Visual FoxPro中,下列叙述错误的是( )。

A. 关系也被称作表
B. 数据库文件不存储用户数据
C. 表文件的扩展名是.Dbf
D. 多个表存储在一个物理文件中

在Visual FoxPro rfl,可以对项目中的数据、文档等进行集中管理,并可以对项目进行创建和维护的是( )。

A. 工具栏
B. 设计器
C. 文件编辑器
D. 项目管理器

假定系统日期是2008年1月13日,则执行命令PI=MOD(YEAR(DATEO)-2000,10)后.PI的值是( )。

A. 012008
B. -8
C. 8
D. 0

Why do we along with 75 other countries—alternate between standard time and daylight time Although many people believe it has an agricultural provenance, daylight time has always been a policy meant to save energy. As Benjamin Franklin argued, if people moved up their summer schedules by an hour, they could live by "sunshine rather than candles" in the evenings. Energy conservation was the motivation for daylight time during World Wars I and II and the oil embargo of the 1970s, and it remains so today—even though there has been little scientific evidence to suggest daylight time actually helps us cut back on electricity use. Recently, however, we were able to conduct a study in Indiana, where daylight time was instituted statewide only in 2006. Before that year, daylight time was in effect in just a handful of counties. This change of policy offered a unique, natural experiment to measure the overall effect on residential electricity consumption. We could compare the amount of energy used by households in the late-adopting counties during the two years before they switched to daylight time with the amounts they used during the year afterward—while using counties that always practiced daylight time as a control group. We found that daylight time caused a 1 percent overall increase in residential electricity use, though the effect varied from month to month. The greatest increase occurred in late summer and early fall, when electricity use rose by 2 percent to 4 percent. Daylight time costs Indiana households an average of $3. 29 a year in higher electricity bills, or about $ 9 million for the whole state. We also calculated the health and other social costs of increased pollution emissions at $1.7 million to $5.5 million per year. What explains this unexpected result While daylight time reduces demand for household lighting, it increases demand for heating in the early spring and late fall(in the mornings)and, even more important, for cooling on summer evenings. Benjamin Franklin was right about candles, in other words, but he did not consider air-conditioners. In regions of the United States where demand for air-conditioning is greater than in Indiana, this spike in cooling costs is likely to be even greater. Arizona, one of the hottest states, may have it right; it does not practice daylight time. Eliminating daylight time would thus accord with President-elect Barack Obama"s stated goals of conserving resources, saving money, promoting energy security and reducing climate change. At the very least, we should abandon the notion that we are saving energy while enjoying the extra hour of sunlight on hot summer evenings. It was in Indiana that a study was conducted because______ .

A. only a few counties there adopted daylight time before 2006
B. the effect of daylight time on electricity use could be measured
C. it was the only state in America to adopt daylight time statewide
D. the late-adopting counties consumed less electricity than before

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