— I didn’t know you were friends with Mr. Smith.

— We ______ each other for6 years.

A．knew

B．are known

C．have known

D．will know

( )是产品质量水平和质量体系中各项质量活动进行及结果的客观反映，是证明各阶段产品质量达到要求和质量体系运行有效的证据。

A．质量手册

B．程序文件

C．质量计划

D．质量记录