The surfaces of {HEAD ~ the rotor} that are exposed to the gases of combustion are provided with {TAIL ~ a plurality} of pockets 
The surfaces of { HEAD ~ the rotor } that are exposed to the gases of combustion are provided with { TAIL ~ a plurality } of pockets
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH