强迫振动的频率与系统的固有频率接近。
参考答案:对
—Do you still work in the factory ________ is friendly to you?
—_______, it is two years since I worked there.
A.whose manager; Yes
B.the manager of which; Yes
C.of which the manager; No
D.which manager ;No
跳汰机的给煤量一定要均匀、连续、稳定。