LDI和LD分别取常开和常闭触点，并且都是从输入公共线开始。
参考答案：错
33．Unemployment is on the increase. A growing number of young people,____, are finding themselves out of work.
A．in case
B．all in all
C．in particular
D．as a result
当发生细粉分离器堵塞时有何现象？
