Under these circumstances, {HEAD ~ the first and the second supporting members} are fixed to the first and the second axles respectively, and the first and the second axles can provide {TAIL ~ pivoting activities} 
Under these circumstances , { HEAD ~ the first and the second supporting members } are fixed to the first and the second axles respectively , and the first and the second axles can provide { TAIL ~ pivoting activities }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL