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