A re-heater in an air conditioning system functions to ______.A.control inlet air temperat

By "rarefaction" of the air, the author means ______.

A．reduction of the density of the air

B．purification of the air

C．removal of oxygen from the air

D．the rising of the air

A.an air

B.air

C.the air

D. airing

A．F．B．means Air()Bill．

A．Free

B．Freight

C．Foreign

D．Full

A.with air

B.in air

C.by air

D.through air

_____ supplies pilot air to control the cylinder air start valves.

A.An air compressor

B.An indicator cock

C.An air distributor

D.A safety valve