Children under sixteen are not permitted to see such kind of films as ________ bad for their mental

development.[ ]

A. was        

B. were

C. is  

D. are

KTC和SQ3X系列切丝机排链传动链轮、链条磨损，会造成排链运动速度过慢，进而使烟饼推进速度不稳定，导致切丝宽度不均匀。