{HEAD ~ The apparatus} comprises a first chamber, {TAIL ~ a second chamber} connected to the first chamber, and a third chamber connected to the second chamber 
comprises
{ HEAD ~ The apparatus } comprises a first chamber , { TAIL ~ a second chamber } connected to the first chamber , and a third chamber connected to the second chamber
HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH