在交换机的帧转发方式中，__________方式具有帧差错检测能力，并能支持不同输入/输出速率的端口之间的帧转发，缺点是交换延迟时间将会加长。

—He looked so scary that the kids were really _____.  

—He often uses that _____ look to frighten them.   [ ]

A. frightened; frightened                    

B. frightened; frightening  

C. frightening; frightened                    

D. frightening; frightening