{HEAD ~ The first valve} is provided in {TAIL ~ the first connection passage} to open and close the first connection passage 
is provided in
{ HEAD ~ The first valve } is provided in { TAIL ~ the first connection passage } to open and close the first connection passage
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH