AT89S51的定时器/计数器对外部脉冲进行计数时,要求输入的计数脉冲的高电平或低电平的持续时间不小于1个机器周期。
查看答案
压片时哪些因素会造成片重差异超限
A. 颗粒细粉太多
B. 颗粒太潮
C. 颗粒流动性差
D. 压力过大
E. 加料斗内的颗粒时多时少
Q:Can you guess who Abraham, Martin, John &Bobby are?A: They are_____________, ________________, President __________________&_____________________,John Kennedy’s brother.
Q:What did these people stand for?A:They represented the __________ leaders, who advocated ___________ civil- rights.
Q:Do you know why they all died young & who killed them?A:They were all _____________ young because they fought for the civil-rights, which resulted in ____________.