The news came as no surprise to me. I _____ for some time that the factory was going to shut down.

A．had known

B．knew

C．have known

D．know

设备通过良好的润滑可以达到以下目的（）。

A.保证正常运转，防止事故发生

B.减少磨损，延长使用寿命

C.提高和保持生产效能，加工精度

D.正确合理润滑，节约用油，避免浪费