{HEAD ~ The present invention} is directed to {TAIL ~ an eraser} for collecting dust, i.e., chalk dust, released from a surface, i.e., a chalkboard 
is directed to
{ HEAD ~ The present invention } is directed to { TAIL ~ an eraser } for collecting dust , i.e. , chalk dust , released from a surface , i.e. , a chalkboard
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH