反馈控制系统受到阶跃扰动后,被控量振荡4~5次稳定下来,这说明()。
A.控制对象K↑,T↓
B.控制对象K↓,T↑
C.调节器控制作用较弱
D.调节器控制作用偏强
参考答案:D
325×7的积是[ ]
A.两位数
B.三位数
C.四位数
Life insurance, before available only to young, healthy persons , can now be obtained for old people, and even for pets.
A.before young, healthy persons available only,
B.available only to young, healthy persons before,
C.available only to persons young, but more healthy,
D.before young and healthy persons only available to,