--- Can you tell me________?

--- I lost my MP3 player.

A．what’s the matter with you

B．what the matter is with you

C．what the matter you is

D．what the matter with you are

由于磨擦面间有油膜存在，作用在磨擦面上的负荷比较均匀地通过油膜分布在磨擦面上，这种润滑称为（）作用。

A、减振

B、保护

C、卸荷

D、冷却