--- Excuse me, sir. Would you please             the total cost of the trip?

--- All right, I will make it at once.

A．look out

B．put out

C．go out

D．work out

下列选项中哪些是滤油器按结构形式分的（）。

A、网式

B、烧结式

C、线隙式

D、电喷式