The processing unit receives {TAIL ~ a query} for an item and uses the features index to determine search results including the item, such as {HEAD ~ a location} and a time of the item 
The processing unit receives { TAIL ~ a query } for an item and uses the features index to determine search results including the item , such as { HEAD ~ a location } and a time of the item
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH