He ________ the naughty children and they kept silent at once.[ ] 

A. glared at  

B. stared at

C. looked at  

D. glance at

三相笼型异步电动机电源反接制动时需要在（）中串入限流电阻。

A、控制回路

B、定子回路

C、转子回路

D、直流回路