One of his friends from the United Kingdom. [ ]
A. come
B. comes
C. coming
D. to come
答案:B
目前实验室用的打点计时器有______计时器和______计时器两种,它们所接电源均为频率为50Hz的交变电流,所以都是每隔______s打一个点.但前者所接交流电压为______V,后者所接交流电压为______V.
下面程序的运行结果为 #include<iostream.h> void main( ) char a=’3’; switch(a) case’3’:cout < <"3"; case’2’:cout < < "2";break; default:cout < <"1"; A) 3 B) 321 C) 31 D) 32