二阶环节G(s)=10/(S2+3.6S+9)的阻尼比应为()
A.ξ=0.6
B.ξ=1.2
C.ξ=1.8
D.ξ=3.6
参考答案:A
以下球类中质量接近1千克的是 [ ]
A、足球
B、羽毛球
C、铅球
D、乒乓球
()in the leg, the soldier was sent to hospital at once.
A.Seriously injured
B.To be seriously
C.Being injured seriously
D.Having injured