【简答题】AT89S52单片机有(__)个脚,其中第40脚和第20脚分别为(__)和(__), 18、19脚外接(__)而构成振荡系统,为保持时钟标准,外接两只(__)作为补偿
【判断题】单片机AT89S52有40个管脚,其中第20号管脚是GND
【简答题】Mike come s from Canada . He is a ______________ boy. He speak s _______________ .
【单选题】分析下段代码输出结果是( ) var arr = [2,3,4,5,6]; var sum =0; for(var i=1;i < arr.length;i++) { sum +=arr[i] } console.log(sum);
【判断题】单片机AT89S52有40个管脚,其中第40号管脚是VCC
【单选题】为验证某种商品在当地市场销售前景,提供可靠资料,可采用的调查方法是
【单选题】From the passage we can conclude that the U.S. has come to realize______.
A.
the weakening if the U.S. dollar can result in trade deficits
B.
the lower the retail prices, the greater the profits
C.
tourism can make great contributions to its economy
D.
visitors to the U.S. are wealthier than U.S. tourists abroad