{HEAD ~ a noise reducing groove} formed at an upper surface of the pump cover and having {TAIL ~ a predetermined length}; and 
having
{ HEAD ~ a noise reducing groove } formed at an upper surface of the pump cover and having { TAIL ~ a predetermined length } ; and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH