For example, {HEAD ~ a hard metal} may be used to prevent the damage caused by {TAIL ~ the shock} 
For example , { HEAD ~ a hard metal } may be used to prevent the damage caused by { TAIL ~ the shock }
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL