{TAIL ~ The processing process} of {HEAD ~ the recessed hole} in the box end of the wrench is also complicated  
{ TAIL ~ The processing process } of { HEAD ~ the recessed hole } in the box end of the wrench is also complicated
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH