However, {TAIL ~ this valve mechanism} involves {HEAD ~ a large number} of parts and results in a complicated configuration 
However , { TAIL ~ this valve mechanism } involves { HEAD ~ a large number } of parts and results in a complicated configuration
OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH