用C语言编写AT89C51单片机时,必须添加的头文件是“reg51.h”。
查看答案
已知∆ABC中,a=20,b=29,c=21,求∠B=( )
A. 60°
B. 45°
C. 90°
D. 120°
A newborn baby needs _____________ care and attention.
A. constancy
B. constant
C. contain
D. constrain
These large companies ___________ considerable infl uence over the government.
A. exit
B. exert
C. exist
D. existing
Winning the championship was a / an _______________ feeling.
A. increased
B. Incredible
C. indifferent
D. differ