{HEAD ~ Such calculations} can be done on {TAIL ~ a classical computer}; the hope is that they can be done much faster on a quantum computer 
done on
{ HEAD ~ Such calculations } can be done on { TAIL ~ a classical computer } ; the hope is that they can be done much faster on a quantum computer
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH